The bios can recognize the hard disk, but the system cannot identify the solution.

This is because of improper use of your hard disk (bad track test method: in DOS, run the command SCANDISK/ALL and press Enter. During disk scanning, if one or several black-colored "B" characters appear, it indicates that the hard disk has a bad track.) the consequence of a bad track is that the light hard disk cannot be used at all.

How can this problem be solved?

At this time, you need to ask for "low-end software", which can generally bring the hard disk back to life.
There are many low-end software, such as DM, SmartFdisk, and QAPLUS.
Or use the low-level format of the LFORMAT that comes with DOS, and then use the FDISK partition.

Several methods for restoring hard disk data when partition tables are damaged

I. Partitions for hard disk data recovery

The first thing you need to do with your hard disk is partitioning. Whether the hard disk partition is reasonable directly affects the convenience of future work and data security. The most common partition table error is also the most serious disk error. Different errors may cause different losses. If there is no active partition flag, the computer cannot start. However, you can read and write the hard disk after the drive or drive boot system. You can use fdisk to reset the active partition to repair the disk. If a partition type is incorrect, the loss of a partition may occur.

After hard disk partitioning, three forms of partition status are formed: primary partition, extended partition, and non-DOS partition. Non-DOS Partition (Non-DOS Partition) in a hard disk is a special Partition form, which separately divides one area of the hard disk for use by another operating system, for the operating system of the primary partition, it is a partition of storage space. Only the operating system in a non-DOS partition can manage and use this storage area. Systems outside the DOS partition generally cannot access the data in this partition.

The primary partition is a relatively simple partition, usually located in the first area of the hard disk, forming a logical C disk. The main bootstrap program is a part of it. This program is mainly used to check the correctness of the hard disk partition, determine the active partition, and hand over the boot permission to the DOS or other operating systems of the active partition. If the program is damaged, it cannot be booted from the hard disk, but the hard disk can be read and written after the software or optical area.

The concept of extended partitions is complex, which can easily lead to confusion between hard disk partitions and logical disks. The fourth byte of the partition table is the partition type value, normally, the basic DOS partition value larger than 32 MB is 06, and the extended DOS partition value is 05. If you change the basic DOS partition type to 05, the system cannot be started and the data in the partition cannot be read or written.

If you change 06 to DOS, for example, efh, DOS considers that the partition is not a DOS partition and cannot be read or written. Many people use this type of value to encrypt a single partition and restore the original correct type value to restore the partition to normal. There are other data in the partition table used to record the start or end address of the partition.

Damage to the data will lead to confusion or loss of the partition and generally cannot be restored manually. The only method is to re-write the data in the backup partition table, you can also obtain partition table data from other hard disks of the same type and with the same partition status. Otherwise, other data will be lost permanently.

The microcomputer operating system only reserves 64 bytes of storage space for the partition table, and the parameters of each partition occupy 16 bytes. Therefore, the operating system can only store data in four partitions, in actual use, the four logical disks often cannot meet the requirements. We often say that the hard disk expansion partition is just a pointer to the next partition. This pointer structure will form a one-way linked list. Therefore, the loss of the logical disk may occur if a problem occurs in the one-way linked list.

II. Hard disk data recovery

1. Recover accidentally formatted hard disk data

In the high DOS version, the formatting operation format creates disk information for restoring formatting by default. In fact, the DOS boot sector of the disk is used, all contents of the fat partition table and directory table are copied to the last several sectors of the disk (because the following sectors are rarely used), and the content in the data area is not changed at all.

We all know that there is a very good tool UnFormat in the DOS era, which can restore the disk cleared by the Format command. If you mistakenly formatted a partition using the Format command in DOS, you can try this command. However, UnFormat can only recover the local hard disk and software drive, but not the network drive. In addition to the anti-formatting function above, the UnFormat command can also repair and create a corrupt partition table on the hard drive.

However, at present, UnFormat is a bit "Powerless", and the method of restoring the formatted partition by using it is a bit outdated. We can use a variety of restoration software for hard disk data recovery, for example, you can use restoration software such as Easyrecovery 6.0 and Finaldata2.0 to conveniently recover data from hard disks. In addition, DOS also provides a miror command to record the information of the current disk for formatting or restoration after deletion. This method is also effective.

2. Hard disk data recovery when no track is damaged

The primary boot record area (MBR) of the hard disk is on the zero track. MBR is located in the zero track, zero cylinder, and one sector of the hard disk. The main boot program of the hard disk and the partition table of the hard disk are stored. In the 512-byte hard drive primary boot record sector, 446 bytes belong to the hard drive primary boot program, 64 bytes belong to the hard drive partition table (DPT), and two bytes (55 AA) belong to the partition end mark.

If the zero track is damaged, the Master Boot program and partition table information of the hard disk will be seriously damaged, resulting in hard disk boot failure. 0 track damage judgment: the system can pass self-check, but when starting, the partition is lost or the C directory is lost, the hard disk appears regular "squeaking ...... Run SCANDISK to scan the drive C. A red "B" appears in the first cluster, or the hard disk cannot be found on the Fdisk, and the DM stops on the 0 track, in this case, the zero track is damaged!

Zero track damage is one of the hard disk bad tracks, but its location is very important, so once damaged, it will have serious consequences. If the zero track is damaged, the current normal method cannot completely restore the data. Normally, the zero track is damaged to the hard disk. You can use the pctools de disk editor (or DiskMan) to make the 0 track deflection a sector, use 1 track as the 0 track for use. However, the data can be restored by cluster through Easyrecovery, but the data cannot be completely restored.

3. Data repair when the partition table is damaged

The sector where the hard drive's primary boot record (MBR) is located is also the focus of virus attacks. By damaging the DPT (partition table) in the primary boot sector, you can easily damage the hard drive partition information, damage data. Partition table corruption is caused by the destruction of partition data and the destruction of records. Therefore, we can use software for repair.

Generally, after a hard disk is partitioned, you need to back up a partition table to a floppy disk, a CD, or a mobile storage activity disk. In this regard, KV3000 series and rising, the well-known anti-virus software in China, provide a complete solution. However, although KV3000 also provides a solution for hard disks that do not have partition tables backed up, the success rate is much lower.

In terms of restoring partitions, the Norton Disk Doctor NDD is an absolutely powerful tool that can automatically repair partition loss and other situations. It can rescue data in bad areas of a floppy disk and forcibly read the data and move it to other blank fan areas. In the case of a hard disk crash or exception, it may bring a glimmer of hope to users.

After a problem occurs, start it with the boot disk, run NDD, and select Diagnose for diagnosis. NDD scans the hard disk comprehensively. If there is an error, it will prompt you, and then you only need to select a repair project based on the software prompts, and these problems can be easily solved.

In addition, DiskMan, a familiar Chinese disk tool, has very practical functions in rebuilding partitioned tables. It is most appropriate to fix partition table damage. If the hard disk partition table is seriously damaged by the partition adjustment software (or virus), it will inevitably cause serious consequences of the hard disk and system paralysis. DiskMan can re-create the partition table through the undamaged partition boot record information.

If you select "recreate table sharding" in the toolbar of the menu, DiskMan searches for and recreates the partition. During use, DiskMan first searches for the hidden sector where the 0-cylinder 0 Head starts from the 2-sector, and finds the partition table that has been moved by viruses. Search for the first sector of each head.

The entire search process is carried out by means of "automatic" or "interaction. Automatically retains each detected partition, which is applicable to most cases. The interaction mode prompts you whether to retain each partition. When an incorrect partition table is faulty, we can use the interactive mode to re-search.

However, the rebuilding of the partition table cannot ensure that the hard disk partition table is restored. So remember to protect your hard disk if you want to protect your hard disk! We recommend that you back up partition tables to avoid hardware damage and virus intrusion;

If you do not have a backup, download a DISKGEN software and select the backup partition table in the tool options. Generally, the backup is to the soft drive by default. If you do not have a soft Drive, you need to change the path and output it to the hard disk directory. Then you should burn the backup file to a CD or copy it to a USB flash disk. Do not put it on the hard disk. This is just like the effect of no backup!

4. Hard disk data recovery after deletion by mistake

During computer use, the most common hard disk data recovery is the hard disk data recovery after deletion by mistake. However, remember to never write information to the partition or disk, because the deleted files are most likely to be restored. In fact, after the hard disk partition is deleted using fdisk, the data on the hard disk disappears completely. If the data is not formatted, the hard disk will display an invalid drive.

If you understand how fdisk works, you will know that fdisk only rewrites the content in the primary boot sector of the hard disk (0 sides, 0 sectors, 1 sectors. Specifically, the partition table information of the hard disk is deleted, and the data of any partition in the hard disk is not changed. Because the deletion and formatting operations do not actually touch the data part of the file, this provides a possibility for file recovery.

We only need to use some anti-deletion software (it works by comparing the partition table to restore files), users can easily achieve the purpose of file recovery. At the same time, the mistaken formatting method is basically the same as the accidental deletion restoration method, as long as the partition hard disk is not disrupted using the Fdisk command (use the FDISK command to partition hard disks within 40 GB, it is very convenient and practical. There are all boot disks and there is no problem with the motherboard support ).

The cluster occupied by the file to be restored is not occupied by other files. In this way, most of the data before formatting can still be recovered. In addition, if your Windows system can still be used normally, the simplest restoration method is to use the Windows EasyRecovery software, which has a powerful function to restore hard disk data, not only can files cleared from the recycle bin be restored, but also files in the formatted FAT16, FAT32, or NTFS partition be restored.

The software is easy to use. After decompression and installation, run EasyRecovery and the main interface is displayed. Four functional buttons on the left and two software support buttons, disk diagnostics can help us test potential hardware faults, monitor and report potential drive failures, View Drive space usage details, IDE hard drive jumper settings, analyze file structures, and create bootable diagnostic disks. In addition, the hard disk data recovery options provided by the six function buttons are crucial for the recovery of hard disk data we need. EasyRecovery Professional provides a variety of hard disk data recovery options.

Including: use advanced options to customize the hard disk data recovery function, find and restore deleted files, restore files from a formatted volume, and restore any file system structure information. This software also saves recovery data progress and create a bootable emergency boot floppy disk.

In practice, we will select the advanced option custom hard disk data recovery function for hard disk data recovery. After scanning, the system will display the disk drive information. Here we select the hard disk partition C disk for data recovery, follow the prompts and click "next".EasyRecovery ProfessionalThe partition is automatically scanned, and all detailed file information is displayed.

This includes existing and deleted files. Next, select the file you want to restore and select "next" to go to the selection target location screen. After a while, EasyRecovery will successfully retrieve the lost file, click "cancel" to exit the tool.

EasyRecovery software introduction:

The data recovery software EasyRecovery is a non-destructive read-only application that is safe, inexpensive, and operated by users. It does not write anything to the source drive, it will not make any changes to the source drive. It supports recovering deleted or lost files from a variety of storage media, including hard drive, optical drive, flash memory, and other multimedia mobile devices. To keep deleted or lost files on the drive, all recovered files must be saved to another storage device or another drive in the system. The data recovery software EasyRecovery can restore deleted files by using the command line, application, file system, or recycle bin. The data recovery software EasyRecovery scans the drive and displays a list of files that can be restored from the scanned drive. You can recover a formatted or lost drive, a drive with severe damage to the logical file system, or even a lost RAID! The email recovery module Restores deleted emails.