Boot viruses: we recognize the enemy in person

Despite the many advantages andThe revolutionary convenience of the Windows operating system, it has one major drawback. To be more precise, we are talking about the susceptibility of the system to attacks of viruses of various types and origins. Let's talk about what boot viruses are, how they act, what harm they can do to your computer, and how to deal with them.

You began to notice that the computer started to hangalmost immediately after passing the BIOS tests? Reinstalled the system several times or formatted the hard disk, but did not notice any positive changes? Be careful, because this is the first alarm signal indicating that so-called boot viruses have settled on the computer.

Their main feature is the arealesions. This type of virus infects the disk boot sector. Moreover, they penetrate into the RAM even before the antivirus program. That is why to find them, as a rule, is quite difficult.

Boot viruses do not always carrydestructive functions. However, even in this case, they remain extremely dangerous. Why? Everything is very simple. Errors in programming cause the unstable operation of the operating system, you can lose a lot of important data in the computer's memory. And the installation of a “non-native” system in general can have an unpredictable effect.

Ensure the presence of boot virusIt is possible by tracing the interception of interrupt vectors before directly loading the operating system. In the process of transferring control to the master boot record (MBR) sector, all interrupts are processed exclusively with the help of the BIOS. This significantly reduces the range of addresses. A boot virus in one way or another will intercept some interruptions due to which it can function. As a rule, the combination includes 13h (disk), 8h or 1Ch (timer), 9h (keyboard), 12h (memory size), 21h (MS DOS), 17h (printer). By slightly changing the bootloader, you can see these interceptions, that is, detect the presence of viruses.

If in time it is not found that in the computerboot viruses have got, you can run into big problems, the minimum of which is the need to reinstall the system after cleaning and format the hard disk. In particularly difficult cases, the possibility of re-installing the system may not be.

Prevention and treatment of computer virusescarried out using special tools. For example, the Norton Disk Doctor ("Norton Disk Doctor") has superbly recommended itself against boot viruses. What else can you do?

1.Disconnect the hard drive from your PC and connect it to another computer with the antivirus installed (preferably, it was a high-quality licensed program). After the check of the winchester and the treatment of the found viruses is completed, you can reconnect the hard drive to your computer.

2. Add the function of booting from a CD into the BIOS, and then boot the computer using the “emergency” disk. The disk should contain antivirus software, as well as fresh databases to it.

3. Find a specialist who, taking into account the characteristics of your software, can manually rewrite the boot sector. This process is long and laborious, but it is 100% efficient.