Virus be gone

I let my anti-virus expire, and time passed and eventually my old Toshiba became slower and I realized I'd been infected. A two hour scan by TrendMicro's free HouseCall online scanner revealed that my PC had become host to a number of worms, which were sending crap-emails using my PC.

Once the scan finished, it automatically cleaned up the mal-ware and I am virus free once more. Now I have to get a new copy of Norton AntiVirus and load it so I can stop worrying about this being a repeat event.

I remember about fuive years ago when I was still cynical about anti-virus software, and believed most 'virus' activity was just user error or a system error. I guess it's only a matter of time before any PC left unprotected gets infected these days.

I'm wondering if my new Linux Mandrake system needs AV protection?