We can judge by the following methods.
First, anti-virus software scanning method
This is probably our most preferred friend, I am afraid is the only choice, now more and more virus species, concealment means more and more sophisticated, so to kill the virus has brought new difficulties, but also to anti-virus software developers to bring challenges. However, with the technical improvement of computer programming language and the more and more popular computer network, the development and spread of virus is becoming more and more easy, so anti-virus software development company is more and more. But at present more well-known or so several systems anti-virus software, such as Jinshan poison PA, KV300, KILL, Pc-cillin, VRV, Rising, Norton and so on. As for the use of anti-virus software in this will not have to say, I believe we all have this level!
Ii. observation of the law
This method can be accurately observed only in the understanding of the symptoms of some viral seizures and the place where they are often housed. such as hard disk boot often occurs when the panic, the system boot time is longer, the speed is very slow, cannot access the hard disk, appears the special sound or the prompt and so on above in the first big point appears the breakdown, we first must consider is the virus in the mischief, but also cannot a Dong Ying pan go to the end, above I did not speak the soft, Hardware failure also may have those symptoms! For viruses, we can look at the following:
1. Memory observation
This method is commonly used for viruses found in DOS, we can use the "mem/c/p" command under DOS to view the memory of each program, found that the virus occupied memory (generally not alone, but attached to other programs), some viruses occupy memory is also relatively covert, with "mem/c/p "We can't find it, but we can see that the total basic memory 640K is less than 1k or a few K."
2. System configuration File Observation method
Such methods are generally applicable to hacker class programs, such viruses are generally hidden in the System.ini, Wini.ini and startup groups, in the System.ini file has a "shell=" item, and in the Wini.ini file has "load=", "run=" items, These viruses typically load their own programs in these projects, and note that sometimes you modify an existing program. We can run the Msconfig.exe program in Win9x/winme to see one item.
3. Characteristic string observation method
This approach is mainly targeted at some of the more specific viruses, these viruses will write the corresponding characteristics of the code, such as the CIH virus will be in the intrusion file to write "CIH" such a string, of course, we cannot easily find that we can be on the main system files (such as Explorer.exe) Using the 16 code editor to edit can be found, of course, before editing the best to back up, after all, the main system files.
4, hard disk space observation method
Some viruses don't damage your system files, but only to generate a hidden file, this file generally very little, but the space is very large hard disk, sometimes large to make your hard drive can not run the general program, but you look and see it, then we will open the resource manager, Then set the properties of the view to view all properties of the file (this method should not be for me?), I believe this leviathan will definitely come when it appears, because the virus generally set it to hide properties. To delete it, this example in My Computer network maintenance and repair of personal computers to see a few examples, obviously only installed a few common programs, why in the C disk a few g of the hard disk space display is not, after the above method can quickly let the virus visible.