Webmasters teach you how to identify viruses

In the process of eliminating computer viruses, some computer viruses are caused by computer hardware or software faults, and some virus outbreaks are similar to hardware or software faults, such as Boot viruses. This causes a lot of trouble for users. Many users often format the hard disk when they can't find the virus by using various virus scanning software, which not only affects the hard disk life, it cannot solve the problem fundamentally. Therefore, correctly distinguishing computer viruses and faults is the key to ensuring the safe operation of computer systems.

I. Computer Viruses

Under normal circumstances, computer viruses always multiply and spread by a system software or user program. During a virus attack, the normal operation of the computer is endangered, data and programs are damaged, and computer resources are infringed. After a computer is infected with a virus, exceptions always occur regularly:

1. The screen display is abnormal. The screen displays a picture or string that is not produced by a normal program, and the screen is messy;

2. The program loading time increases, and the file running speed decreases;

3. the device that the user has not accessed has a working signal;

4. the disk contains inexplicable files and Bad blocks, and the volume label changes;

5. system self-guided;

6. data or programs are lost, and the number of file bytes changes;

7. Reduced memory and disk space;

8. Abnormal crashes;

9. The disk access time is longer than usual;

10. The system boot time increases.

If the above problem occurs, you should first perform the BOOT zone and IO on the system. SYS, MSDOS. SYS, COMMAND. COM ,. COM ,.. Check other files to identify the causes of exceptions. The key to the difference between a virus and a fault is that a fault occurs occasionally and occasionally, while a virus attack is always regular.

Ii. hardware faults similar to viruses

The hardware fault scope is not extensive, but it is easy to be confirmed. When dealing with computer exceptions, it is easy to ignore. Only hardware faults are eliminated first, which is the root cause of the problem.

1. system hardware configuration

This kind of fault often occurs on compatible machines. Due to the incompatible accessories, some software may not run properly. I have encountered a compatible machine, lianxun green energy-saving motherboard, and kunteng big-pin hard drive. The installation of small software started very smoothly, but the installation of WINDOWS failed, at first, I began to suspect that the virus was a strange thing. After using a lot of anti-virus software, the problem could not be solved. Later, I checked some materials to find out the problem. Because the motherboard is energy-saving, but the CPU and hard disk are not energy-saving, when the software installation time exceeds the sleep time of the motherboard, the motherboard enters the sleep state, so the fault occurs due to the incoordination of the motherboard, CPU, and hard disk. The solution is very simple. It is normal to turn off the energy-saving switch of the motherboard. Therefore, users should first consider the compatibility of accessories when assembling their own computers, and carefully read the product manual before purchasing accessories.

2. unstable power supply voltage

Due to the unstable voltage of the power supply used by the computer, user files may be lost or damaged during disk read/write. In severe cases, the system may start automatically. If the voltage of the user's power supply is often unstable, we recommend that you use a power regulator or uninterruptible power supply (UPS) to make your computer work more securely ).

3. Poor plug-in contact

Due to poor computer plug-ins, some devices may experience good and bad times. For example, when the display signal line is not in good contact with the host, the display may be unstable; when the disk line is in bad contact with the multi-function card, the disk read/write may be good or bad; when the printer cable is in bad contact with the host, the printer may not work or work properly. When the mouse cable is in bad contact with the serial port, the mouse may fail to move.

4. Soft drive failure

If you use a disk of poor quality or a damaged or moldy disk, the drive head will be corrupted and the disk may fail to read or write. In this case, you only need to use a cleaning disk to clean the head. In general, You can queue for faults. If the pollution is very serious, you need to detach the soft drive and use the cleaning liquid for manual cleaning.

5. CMOS Problems

As we all know, the information stored in CMOS is very important to computer systems, when a microcomputer is started, it is always necessary to detect and initialize the system according to the information in CMOS (of course, the most basic initialization ). Most of the Boards above 486 have a virus monitoring switch, which is usually set to "ON". If Windows 95 is installed, the system will crash. The reason is that when Windows 95 is installed, the installer modifies the boot part of the hard disk, the internal interruption and interruption vector table of the system, and the virus monitoring program does not allow this, resulting in a crash. We recommend that you first turn off the virus monitoring switch in CMOS when installing a new system. In addition, the system boot speed and the running speed of some programs may also be related to CMOS, because there are some shadow memory switches in the advanced settings of CMOS, which will also affect the operating speed of the system.

Iii. software faults similar to viruses

Software faults have a wide range of problems. Identifying and solving software faults is also very difficult. It requires users to have considerable Software Knowledge and rich hands-on experience. Some common symptoms are described here.

1. "Invalid drive specification" (Invalid drive letter) appears)

This prompt indicates that the drive is lost. If the drive is owned by the user, it may be that the Partition Table parameter of the primary Boot Sector of the drive is damaged or the disk flag 50AA is modified. In this case, use tools such as DEBUG or NORTON to write the correct information about the primary Boot Sector to the primary Boot Sector of the disk.

2. software programs damaged (non-virus)

Due to disk quality and other problems, part of the data in the file is lost, and this program can still run. In this case, the usage may be abnormal. For example, if the Format program is destroyed, the disk is formatted in a non-standard format, resulting in a series of errors. However, this problem is extremely rare.

3. Improper dossystem Configuration

When the DOS Operating System is started, it searches for its system configuration file CONFIG. SYS and configures the runtime environment as required. If the system environment is improperly set, some software may not run properly, such as CC ++ language system and AUTOCAD. The reason is that these programs open too many files, exceeding the default value of the system.

4. Compatibility between software and DOS versions

The DOS operating system features lower compatibility. However, the software is different. Many software must be too limited by its environment. software that can run normally in a certain version cannot run normally in another DOS version, many users suspect it is caused by viruses. For example, the old 2.13 Chinese character system runs normally in DOS 3.30, and garbled characters may occur in DOS6.2.

5. Boot Process faults

During system boot, the screen displays "Missing operating system" (the operating system is lost). The fault is that the hard drive's main boot program can complete boot, but the boot records of the DOS system cannot be found. The reason for this is that the C disk does not have boot records and DOS system files, or the type of the hard disk in CMOS is different from that in the format of the hard disk itself. The system file needs to be transferred to the C drive or the CMOS configuration needs to be modified to enable the system to boot from the floppy disk.

6. Use different editing software programs

You can use some editing software to edit the source program. The editing system will mark the file in special places. In this way, errors occur when the source program is compiled or interpreted. For example, a text file edited using the N command of WPS also has layout parameters in its header, but some program compilation or interpretation systems cannot distinguish it from the source program, in this case, an error occurs.

7. FOXBASE Problems

Users who often use FOXBASE may find that some files named after "S" characters or numbers are generated on the disk, and some database files are lost. This phenomenon is very similar to computer viruses. In fact, the main cause of this phenomenon is that after using FOXBASE, the user turns off the machine without going back to the DOS state, or loses power when using FOXBASE. It is recommended that the user shut down after the user returns to the DOS status after using FOXBASE, otherwise it will not only cause the above phenomenon, but also cause damage to the disk.

In the process of learning and using computers, there may also be many software and hardware faults similar to viruses. Therefore, users should read more and refer to relevant materials to learn how to detect viruses, and pay attention to the accumulation of experience in learning and work, it is not difficult to distinguish between viruses and hardware and software faults.