Computer virus detection and removal

In our network life, computer viruses pose a major threat to us. We are very concerned about how to prevent viruses. In fact, the prevention of computer viruses is not simply a few words. Some of us have very many mistakes in our understanding, next, let's take a look at the top 15 mistakes we made in the face of computer viruses.

The DIR operation on the infected floppy disk may cause the hard disk to be infected.

If the computer memory does not contain viruses, the computer will be infected only after a program (File) with viruses is executed. The DIR command is an Internal DOS command and does not need to execute any external programs (Files). Therefore, the DIR operation on the infected floppy disk will not infect the virus.

However, if the computer memory is infected with viruses (or the computer is infected with viruses), if you perform the DIR operation on a non-infected floppy disk, the disk may be infected. It may be infected because some viruses do not spread through the DIR operation.

Change the file to read-only mode to avoid virus infection.

Some people think that setting the file to read-only through the external DOS command ATTRIB can effectively defend against viruses. In fact, you only need to call a few DOS interruptions to modify the attributes of a file. Therefore, the ATTRIB command is almost powerless to prevent virus infection and spread.

A virus can infect a write-protected disk.

Because the virus can infect read-only files, many people think that the virus can also modify files on the write protection disk. In fact, the disk drive can determine whether the disk is write-protected and whether write operations should be performed on it. This is all controlled by hardware. You can physically remove the write-protection sensor of the PC, but it cannot be done with software.

If your drive is normal, and the write protection of the floppy disk is not removed once, it will never be infected with viruses. However, if you remove the file and use the DIR of the infected machine, the file may be infected with the virus. Note that this DIR is infected with a virus from the machine to the floppy disk, rather than the virus from the floppy disk to the machine.

The write protection is different from the file read-only mode. The file read-only mode is set through the computer, so the virus can be inserted with one hand. However, the write protection requires human intervention, and the virus cannot remove the write protection. The computer cannot rewrite the write protection disk, which cannot be changed unless you break the drive ).

Anti-virus software can remove all known viruses

There are many virus infections. Some viruses forcibly overwrite a part of the execution program and embed their own code to avoid changing the length of the infected file, the Code covered by such a virus cannot be restored, so the virus cannot be safely eliminated. The virus destroys some content of the file. After the virus is eliminated, the file's original appearance cannot be restored.

Anti-virus software can be used to protect against viruses.

Anti-Virus Software sold on the market can only be used after the virus flood ". However, before virus removal, the virus has caused work delays, data damages, and other more serious consequences. Therefore, a complete anti-virus system should be selected, which should not only include common virus detection and anti-virus functions, but also include real-time anti-virus functions, it can monitor and track various operations on files in real time. Once a virus is detected, an alarm is triggered immediately. Only in this way can the chance of virus infection be minimized.

Disk File Corruption is mostly caused by viruses.

There are multiple causes for file damage: Power Supply voltage fluctuations, power loss, magnetization, poor disk quality, hardware errors, errors in other software, dust, Ash, tea, even a sneeze may cause data loss. The damage to files mentioned above is more common and serious than the damage caused by viruses.

If the backup is defective, it is useless.

There are two cases: ① floppy disk backup: the backup contains Boot viruses. In this case, as long as you try to start your computer without using this floppy disk, it will be as safe as a non-toxic backup. ② Tape backup: There is no virus in the data file in the backup. If the executable file contains a virus, the execution file will be backed up in white, but the data file in the backup is still available.

Anti-virus software can guard against any mold disease anytime and anywhere

Obviously, this anti-virus software does not exist. The emergence of new viruses requires that the anti-virus software be upgraded quickly. What we need for anti-virus is a security policy and a comprehensive Anti-Virus System, which uses backup as the first line of defense against viruses and uses anti-virus software as the second line of defense. At the same time, timely software upgrades are the only way to reinforce the second line of defense. Anti-virus software is used to assist in anti-virus attacks. It cannot be an attack-free license.

Genuine software without viruses can be used safely

Computer users are often told that "do not use unknown software to prevent viruses ". This is good. The so-called "unknown software" is indeed one of the main ways to spread computer viruses. Can I leave it easy to use software with "Origins? None! In fact, computer newspapers and media have repeatedly reported "genuine software ". "Product software" is infected with viruses. Product software cannot be used lightly. Even new computers, including original computers, must undergo virus detection before use. If the original software is infected with viruses and causes significant losses, legal protection should be sought.

No floppy disk, no virus, no antivirus software

"No floppy disk, no virus" is a comment that is often heard by beginner users. It is a pair of twin sisters who use a floppy disk to infect viruses, there are two types of incorrect arguments.

Virus Infection is carried out through the software with viruses, but the floppy disk is not the only carrier of the software with viruses. It can be said that wherever a program (software) can be obtained, the virus may be "obtained. That is to say, using CDs, hard disks, tapes, or using or downloading software through a local/wide area network, Internet, or BBS poses a risk of virus infection. Especially in recent years, Internet and BBS have been widely used, making it possible for domestic and foreign viruses to spread widely and quickly. These international computer information dissemination media are potential sources of virus viruses and tubes (of course, these network systems also have a highly secure anti-virus/Anti-Virus System ), this makes every computer user vulnerable to viruses. -I'm afraid no one will say that his computer will never be connected to the Internet.

People cannot not be ill, so computers cannot be infected with viruses. Therefore, you must select anti-virus software.

People cannot all be doctors, so you do not have to face the virus alone, so you must choose anti-virus software.

"Only the antivirus software is enough" and "one antivirus software is enough"

"Only Antivirus" and "one anti-virus software is enough." This is what some people think about when choosing anti-virus software. A common situation is that when your computer is abnormal, it is good to find a lot of anti-virus software, whether it is genuine or pirated. In fact, many computer faults are not caused by viruses. In this way, many anti-virus software are "invalid "; another common situation is that users generally do not pay attention to the difference between "virus detection" and "anti-virus". When using anti-virus software, the "anti-virus" operation is preferred. As a result, when it uses this anti-virus software to "disinfect" the system once, other anti-virus software will no longer find the virus, it is considered that this software is the best.

No antivirus software can cover all viruses. No one can do this. Due to the different origins of virus specimens, coupled with the strength of programmers, there is always a virus that can be detected and killed by software, but other software cannot. Or because of some program bugs (program errors), some software may have been able to scan and kill viruses, but some versions of the software cannot be scanned or mistaken. Therefore, we do not recommend that you choose anti-virus software.

When choosing anti-virus software, you should first put aside all your preferences about "good" and "bad" and reject all the temptations in advertising words, carefully learn about the technical strength, service quality, and software performance of antivirus software vendors. It is particularly important to understand the reliability of software vendor measures and commitments in terms of upgrades, returns, and damages and replacements. At the same time, you should ask the manufacturer to explain the specific meanings of their terms in the advertisement. You must know that this is your legitimate rights and interests as a consumer.

Today's anti-virus software market is like the Warring States period. But consumers feel uneasy. Who is the best software? Is it better to use one or more? There is no "Wan Ling Dan" in the world. A good software, not all viruses can be killed, and it cannot "cure all diseases ". The time for each software manufacturer to obtain a virus sample is different. Therefore, each software manufacturer has its own focus in each time period, and only one is not safe. In addition to the "omnipotent Lord", I am afraid that nothing else can be found in this world. To prevent repeated construction, experts believe that purchasing anti-virus software with two complementary advantages is the best way to improve the security factor. Do not install several anti-virus software on the same computer. Most of them are unnecessary, and there may be problems such as mutual resource preemption, misjudgment, and crashes.

Virus found in CMOS

CMOS is a special memory in a microcomputer. It records the hardware setting parameters of the microcomputer and the system date and time. Power-on password and other important data. Due to the importance of CMOS settings, computer viruses may be the targets of attacks. At present, we have indeed discovered the "CMOS setting destructor" virus for rewriting CMOS, but there is no virus in CMOS.

Sometimes, a problem occurs on the machine. The problem lies in the CMOS settings. Some people think that this is a virus hiding in the CMOS! Therefore, we mistakenly believe that anti-virus software is not good. We adopt discharge and short-circuit measures for the CMOS memory. After setting the CMOS parameters again, the machine returns to normal and we are sure that there is a virus in the CMOS. This behavior and Its danger make it easy to break down the motherboard. Let's say, "CMOS sets the destruction virus, which is not equal to the virus in CMOS! Viruses cannot automatically infect themselves into CMOS and remain and be activated !", "Viruses can change or encrypt CMOS settings, but users can also reset and recover ."

In some cases, such as insufficient CMOS power supply, fluctuation of external power supply impact, software crash, hardware instability, Operation errors, and virus rewriting may cause CMOS setup disorder. You can also say that, it is garbled encryption, so the machine cannot be guided or work properly. In this case, You can reset the CMOS settings and use special software to clean up the random passwords, and then set the correct parameters.

There is no virus parasitic in CMOS, because:

(1) CMOS reads and writes data through I/O and exchanges data with the CPU. The physical function of the CPU determines that only CMOS data can be read and written. Data in CMOS cannot be executed as command code. If a virus wants to work, it must execute its program code. However, CMOS is only used to store data. The data in CMOS is not executable, so there is no CMO5 virus, only viruses that will damage the CMOS Data.

(2) If a piece of virus program is written into CMOS, it will inevitably destroy the hardware settings of the Microcomputer so that the microcomputer cannot run at all, and the "virus program" stored in CMOS will have no effect, viruses cannot spread or hide in CMOS.

(3) effective storage of CMOS