Computer viruses


What are computer viruses?
Let’s first get some facts straight about viruses. Computer viruses are not actually living creatures. They are just programs like any other, except that they copy themselves onto other programs. They “infect” them. They cannot actually run by themselves. To activate a virus, you need to run the program which was infected.
Here is a good example: A computer virus is a self-replicating program containing code that explicitly copies itself and that can “infect” other programs by modifying them or their environment such that a call to an infected program implies a call to a possibly evolved copy of the virus.
From all of this information, you should be able to see that you cannot get infected by a computer virus by just reading e-mail or opening a document. Unfortunately, this is not entirely true. There is a programing language called WordBasic. This is used to write macros for Microsoft Word. It is also used, by some people, to write computer viruses. Those would be started when a document, which is already infected, is opened. Some of these viruses are harmless, while others are very destructive.
I think I have a virus,
what do I do?
So you think you have a virus? Well, maybe you don’t. Many people just think that they have a virus because something is wrong. Perhaps the computer is slower or you can’t read floppy disks any more. Those are not sure signs of infection. There could be some hardware problems instead, or it could be caused by new software that you have installed, or even a change in a configuration file.
The first step to take to check for virus infection is to use a reliable virus scanner/checker. However, no matter how much they tell you how good they are, I recommend using at least two of them. The more famous ones are F-prot, Innoculan, Mcafee, Norton Anti-Virus, Thunderbyte.
After you have installed at least two of them, run them to see if they find a virus on your computer. Be sure to turn “heuristics” off if you can, as that will greatly reduce the number of false alarms. If there is only one infection, it may be a false alarm.
If the scanner tells you it can clean them, you should make a backup copy of all the infected files. You can then let the scanner clean the originals only (not the backups). After you have cleaned them, try running the programs again. If they appear to be working well, then all is fine, and you can delete the backups. If, however, they are not working, then you should delete them, and restore your backups. You should try other scanners, to see if they can remove it. Different scanners can usually remove some viruses that others can’t.
If you can’t find anything that will remove the virus, and you have an uninfected backup, then you should re-install the backup. If you don’t have any backups, then you will have to wait a while for a new update of your anti-virus scanner. During that time, you should not run the infected program under any conditions. If the program is not important, you can always delete it. If you do not know what the file is used for, do not delete it.
After you have finished your new scan, you should do another scan, with a different scanner. That should be done to pick up the viruses that might have been missed by other scanners.
How do I prevent
a virus infection?
The simplest solution is to always leave your computer turned off, but that might not be too useful (and then there is no point in owning a computer). Otherwise, be careful with any new things that you install on your computer. That would include any floppies and anything downloaded from the Internet.
Another thing that you should always do is watch anybody that uses your computer. Other users could bring a virus on, even if they don’t mean to. Of course that is not always possible, so you should consider using a scanner that stays in memory. It checks all files before you open them, and also scans memory when you load it.
This tech Q&A is provided by EntrÃ&Copy; P.C. Solutions, of Brookfield. Small Business Times readers who would like to see a question asked can contact EntrÃ&Copy; at 938-2139 ext. 3022, or visit its Website at

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