In the PC world, viruses which can damage programs happen, but in my experience (and many acquaintances'), rarely.

Do viruses pose a common hazard to Macs and are anti-virus programs effective?
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BatemanConnect With a Mentor Commented:
There are very few virus on the Mac that cause any real damage un like the PC. At the moment the only one I have come across that does cause damage is MBDF which I have seen an increase of latly. This has damamged the system file on many of our networked computers which has only been treated by reinstalling the whole system. The anti-virus programs pick up most viruses, especially if u sign up to their update programs. However I do notice a lot of crashes involved between them and iSDN Manager. Hope this is of help.
Virus writers go after the most common platform, i.e., Intel-based, Microsoft operating systems. I remember back in the late 80's that Mac viruses seemed more common than pc viruses because the Mac was rapidly catching on and growing a larger user base. Now it is the other way around. There are tons more pc viruses than Mac viruses. Part of this has to do with the relatively "closed" architecture of the Mac OS as opposed to the more open one of MS Windows.

I can assure you that pc viruses that are written to harm can do a great deal of damage to your pc, including, but not limited to, zeroing out document files so that they are rendered useless and corrupting system files so that you have to restore your OS from scratch (and lose all date in the process).

Viruses are less common nowadays on the Mac platform but you should still be diligent and use an anti-virus program, especially if you do much work on the internet and regularly use email. The two best are Norton's Anti Virus for the Macintosh and Virex. Check out their web sites for a trial and safe computing!
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