How can I tell if a computer is infected or failed?

The key to ensure the safe operation of computer system is to distinguish virus and fault correctly. How do you distinguish between a computer failure caused by a virus or a computer failure that is not functioning properly?

In the process of cleaning up computer viruses, some of the phenomenon of computer viruses is purely caused by hardware or software failures, while some virus outbreaks are similar to hardware or software failure phenomena, such as guided viruses. This caused a lot of trouble to users, many users often use a variety of anti-virus software to find out the virus to format the hard disk, not only affect the life of the hard disk, but also can not fundamentally solve the problem.

First, the phenomenon of computer virus and the method to find solutions

In general, computer viruses are always dependent on a system software or user programs to reproduce and spread, virus attacks endanger the normal work of the computer, destroying data and procedures, violating computer resources. After the virus infection, the computer always has a certain regularity of abnormal phenomenon:

① screen shows an exception, the screen shows not by the normal program generated images or strings, the screen shows confusion;

② program loading time increases, file running speed drops;

③ the user does not have access to the device appears work signal;

④ disk appears inexplicable files and bad blocks, the volume label changes;

⑤ system to guide itself;

⑥ lost data or program, file byte number changed;

⑦ memory space, disk space reduced;

⑧ abnormal panic;

⑨ disk access time increases than usual;

⑩ system boot time grows.

If this occurs, first the boot area of the system, IO. SYS, MSDOS. SYS, Command.com,. COM,. EXE file for careful examination, and compared with the correct file, if there is an abnormal phenomenon may be infected with the virus. Then the other documents to check, there is no abnormal phenomenon, to find out the cause of the abnormal phenomenon. The key to the difference between a virus and a fault is that the general fault is a random occurrence and the outbreak of the virus is always regular.

It is recommended to use the MSAV software that is in the DOS6.0 version above, and its most prominent function is to be able to detect all changes in the file and to make a record.

If MSAV reports that a large number of files have been altered, the system may be infected with the virus.

Second, similar to the virus phenomenon of hardware failure

The hardware's fault range is not too extensive, but it's easy to verify. When dealing with the abnormal phenomenon of the computer is easy to ignore, only to eliminate the hardware failure, is the root of the problem.

1. Hardware configuration of the system

This kind of fault often occurs on the compatible machine, because the accessory is not completely compatible, causes some software not to be able to run normally. I have encountered a compatible machine, IPs green energy-saving motherboard, Kun Teng Bigfoot hard disk, the beginning of the installation of small software is very smooth, but installed Windows is not installed on the fault, began to suspect that the virus, in the use of a lot of anti-virus software can not solve the problem. Then I looked up some information to find out what the problem was, because the motherboard is energy-saving, and the CPU, hard drive is not energy-saving type, when the time to install the software than the motherboard into the sleep time limit, the motherboard entered the hibernation state, so due to the motherboard, CPU, hard disk work uncoordinated and there has been a failure. The solution is very simple, the motherboard of the energy-saving switch off on all normal. Therefore, users in their own assembly of computers should first consider the compatibility of accessories, purchase accessories should carefully read the product manual.

2. Power supply voltage is not stable

Because the voltage of the power supply used by the computer is not stable, it is easy to cause the user files to be lost or destroyed when they read and write on the disk, which will cause the system to start automatically. In order for your computer to work more securely, it is recommended that you use a power regulator or uninterruptible power supply (UPS) if the voltage of the power supply used by the user is constantly unstable.

3. Bad contact of the plugin

Due to poor contact with the computer, it will make some devices appear good and bad phenomenon. For example: monitor signal line and host bad contact may make the display display instability; Bad contact between disk line and multifunction card will result in good and bad disk reading and writing; Printer cable and host bad contact will cause the printer does not work or work phenomenon is not normal; Mouse line and the serial port is not in contact with the mouse when the movement of the fault and so on.

4. Floppy drive failure

Users if the use of low quality, in fact, the main reason for this phenomenon is the user after using Foxbase, not back to the DOS state to turn off the machine, or in the use of foxbase midway off. It is recommended that users return to Dos after using Foxbase, which will not only cause this phenomenon, but also cause damage to the disk.

In the continuous research and accumulation of experience, we can find a good way. Bad disk or the use of damaged, moldy disk, will be the floppy drive head dirty, there is no read or write disk or error. In this case, just use the cleaning disk to clean the head, under normal circumstances can be queued fault. If the pollution is particularly serious, you need to take apart the floppy drive, wash with the washing liquid hand.

5. With regard to CMOS, it is well known that the information stored in CMOS is very important to the computer system, and it is always necessary to detect and initialize the systems (of course the most basic initialization) by the information in the CMOS when the computer starts up. In more than 486 of the motherboard, most have a virus monitoring switch, the user is generally set to "on", then if the installation of WINDOWS95, will occur panic. The reason is that when you install WINDOWS95, the installer modifies the boot portion of the hard drive, the system's internal interrupts, and the interrupt vector table, which is not allowed by the virus monitor, causing the panic. It is recommended that users in the installation of a new system, the first CMOS virus monitoring switch off. In addition, the system's boot speed and the slow speed of some programs may also be related to the CMOS, because there are some shadow memory switches in the advanced CMOS settings, which can also affect the system's running speed.

Third, similar to the virus phenomenon of software failure

The scope of software fault is more extensive, the problem appears more. Software fault identification and resolution is also a difficult thing, it requires users have considerable software knowledge and rich experience on the machine. Here are some common symptoms.

1. Appearance of "Invalid Drive Specification" (Illegal drive letter)

This hint indicates that the user's drive is missing and that if the user originally owned the drive, the partition table parameters of the main boot sector of the drive may be corrupted or the disk flag 50AA modified. In this case, the correct primary boot sector information is written to the primary boot sector of the disk using tool software such as Debug or Norton.

2. Software program has been compromised (non-virus)

Due to problems such as disk quality, the data part of the file is lost, and this program is still able to run, then there will be abnormal use, such as the format program is destroyed, if continue to execute, will format the non-standard format of the disk, which will produce a series of errors. But such problems are extremely rare.

3. DOS system improperly configured

The DOS operating system will look for its system profile Config.sys at startup and configure the operating environment as required. If the system environment is improperly set up, some software will not function normally, such as cc++ language system, AutoCAD and so on. The reason is that these programs run with too many files open, exceeding the system defaults.

4. Compatibility of software with DOS version

The DOS operating system itself is characterized by a downward compatibility. But the software is different, many software are too much to be limited by their environment, in a certain version of the software can run normally, to another version of the DOS does not work properly, many users suspected to be caused by the virus. The older version of the 2.13 Chinese character system, in DOS 3.30 under normal operation, and in the DOS6.2 run will appear garbled phenomenon.

5. Boot process Failure

The screen displays "Missing Operating system" (lost operating system) while booting, because the main boot of the hard drive completes booting, but the boot record for the DOS system cannot be found. The reason for this is that the C disk has no boot record and DOS system files, or the type of the hard disk in the CMOS is different from the format of the hard disk itself. You need to pass system files to the C disk or modify the CMOS configuration to boot the system from a floppy disk.

6. Use a different editing software program

The user edits the source program with some editing software, and the editing system will make some marks on the special place of the file. This can cause errors when the source program compiles or interprets execution. For example, a text file edited with the n command of WPS has a layout parameter in its head, and some programs compile or interpret the system but cannot distinguish it from the source program, so there is an error.

7. Questions relating to Foxbase

Users who frequently use foxbase may find that some "S" characters or a number of named files are generated on the disk, and some database file data is also found to be missing. This phenomenon and computer virus is very phase