Alien Intruders!

You probably didn’t casually invite, or extend a formal attendance request to, these undesirables known as viruses.
Regardless of your opinions, these cyber-nomads may call on you, complete and active, with their destructive payloads.
So what is a virus?
A virus is a program that can self replicate or reproduce itself.
A boot sector virus is probably the worst in so far as it will upset the normal loading of your operating system and therefore, disable your computer. That’s never a good thing but not the end of the world, however it seems. You can get this virus, without warning but check out the following.
A friend of mine rang me last week in a distressed state, with news that her I.S.P. was threatening to shut down her e-mail account because her computer contained viruses affecting her outgoing mail This message seemed to come from her provider but in fact was created by a worm (type of virus). The e-mail was complete with the providers U.R.L., instructions to open its attachment (which it claimed that it contained a free virus cleaner) and even a password to access the attachment. This password could ”swing” some cautious people to believe that the attachment was legitimate. Indeed there was only one mistake and it was that the e-mail in question was addressed to “Dear account holder” and not her specific e-mail address.
Attachments are potentially dangerous. You should train yourself to look for such things, and not exclusively this. If you have a suspicion, ignore them. If it seems an awful lot more important that account closure warnings (family matters), then simply ring the addressee in question. Surely most other matters can wait until office opening hours in cases where 24-hour telephone support is not an option. Incidentally, the described worm is a BAGLE variant and is currently in circulation and though it can be cleaned, can also be disruptive.

Another virus infects your macros (macro virus) and affects the usability of associated files, which are usually text editors or word processing programs. Turning your macros “off” could be considered, but their benefits are lost and the virus has won, even before entry.
These are harmless enough and there is no need to freak out. A free cleaning option is mentioned below.

Of course, if you can afford it, you should get an anti-virus program. Corporations, companies and anyone without financial restraint have such programs updated continuously as no-one can predict when (in real time) that some virus creator will decide to unleash his newest version. Previous virus definitions are of little use in protecting against future viruses. Such definitions describe the nature (how and where infection occurs) and an engine is used to scan or locate and clean the infected files. Given the reproductive properties of viruses, the amount of such infected files can be enormous and sometimes they are files with particular extensions.
Regular domestic P.C. users should probably update their definitions weekly and there are anti –virus software manufacturers that will scan your machine for free (use your search engine) but it should be remembered that the virus could already be in your machine at this stage. The program that you pay for can block them at all entry points and is the nearest thing to ultimate protection.

Definitive protection requires you to connect to nothing, insert or install nothing, network with no one, and perhaps swabbing your machine with an industrial disinfectant. However, I would consider such measures to be excessive and no way to live your productive life.