The general processing method of the system does not recognize the hard disk

The system can not boot from the hard drive, boot from a disk can not enter the C disk, the use of http://www.aliyun.com/zixun/aggregation/19282.html ">cmos in the automatic monitoring function can not detect the existence of hard disk. Most of this fault occurs on the connection cable or IDE port, the hard disk itself failure is not possible, by reseating the hard drive cable or change the IDE port and cable, etc. to replace the test, you will quickly find fault. If the newly connected hard drive is not accepted, a common reason is the master and slave jumper on the hard disk, if an IDE hard drive cable is connected to two hard disk devices, it is necessary to know the master-slave relationship.

CMOS fault

The correct type of hard disk in CMOS directly affects the normal use of hard disk. Today's machines support the "IDE Auto Detect" feature, which automatically detects the type of hard disk. When the hard disk type is wrong, sometimes it is impossible to start the system, sometimes it can start, but read and write errors occur. For example, the hard disk type in CMOS is less than the actual hard disk capacity, then the sectors behind the hard disk will be unable to read and write, and the individual partitions will be lost if they are multiple partition states. There is also an important cause of failure, because the current IDE supports the logical parameter type, the hard disk can be "Normal,lba,large" and so on, if the general mode of installation of data, and in the CMOS to other modes, then the hard disk read and write error, 　　Because its mapping relationship has changed, it will not be able to read the original correct hard drive location. Boot failure caused by the primary bootstrapper

The main boot program is located in the main boot sector of the hard disk and is used primarily to detect the correctness of the hard disk partition and to determine the active partition, which is responsible for handing over the boot to the DOS or other operating system of the active partition. This piece of program corruption will not boot from the hard drive, but can read and write to the hard disk after booting from the floppy or optical drive. The easiest way to fix this failure is to use a high version of DOS for FDISK, which will replace (override) the hard drive's main boot program directly when you run with the parameter/mbr. Actually, the main boot sector of the hard disk is the program that was created, FDISK. EXE contains the complete hard drive master boot program. Although the DOS version is constantly updated, but the hard drive's main boot program has not changed from DOS 3.x to WinDOS 95 dos, just find a DOS boot disk boot system and run this program to repair.

Boot failure caused by partitioned table errors

Partitioned table errors are a serious error on the hard drive, and different error levels can cause different losses. If there is no active partition flag, the computer cannot start. However, you can read and write to the hard disk after booting the system from the floppy or optical drive, and you can repair it by using the Fdisk reset active partition.

If it is a partition type error, you can cause a partition to be lost. The fourth byte of the partition table is the partition type value, and the normal bootable 32MB primary DOS partition value is 06, while the Extended DOS partition value is 05. 　　Many people use this type of value to implement a single partition of encryption technology, restore the original correct type value to make the partition back to normal. Other data in the partition table is used to record the starting or ending address of the partition. Corruption of this data can result in confusion or loss of the partition, either by using the Backed-up partition table data to be written back, or by obtaining the partitioned table data from other hard disks of the same type and partition status.

Recovery tools can be used NU tools such as software, the operation is very convenient. Of course, debug can also be used, but the operation is cumbersome and has a certain risk.
Fault for partition valid flag error

An important part of the hard drive's main boot sector is the last two bytes: "55AA", which is a valid flag for the sector. When booting from a hard disk, floppy disk, or CD, the two bytes are detected and the hard drive is not recognized if it exists. This can be used for the entire hard drive encryption technology, the debug method for recovery processing. In addition, when the DOS boot sector does not have a boot flag, the system boot will appear as: "Mmissing keyboard-based system". The easiest way to do this is to use a common fix for the following DOS system.