experiences with viruses

I have had two experiences with viruses, both of which required me to lose everything and completely wipe my computers’ hard drives clean. The first time it happened was about three or four years ago when I had just discovered the peer-to-peer file sharing program Limewire. I was using Limewire just to download some music (I think the band was Mr. Bungle). I was not aware that I had downloaded an infected song file until I had clicked on it to play it in Itunes. The worst thing about it was that I was using my mom’s computer that had a whole bunch of her work documents on it. There were frequent, never-ending pop-ups and the computer would crash randomly. After about a week, my dad took it to a computer repair shop. In the end, my mom lost many documents that were important for her work. By the second time, I thought I had learned my lesson. This time, I was downloading torrent of a band’s entire discography from a torrent website. Unlike the first virus I had encountered, this one somehow changed my directories or paths (or something like that, I can’t remember exactly) so that whenever I tried to open a program like Photoshop or even Internet Explorer, a message would pop up saying something like “invalid path”. At that point I had no other option but to re-install Microsoft XP onto my computer from a disc. Fortunately, I had a back up of all my music and some other programs that I had installed before the incident happened. I have since purchased a Mac and am happy that there are virtually no viruses for Mac computers. But I have learned my lesson and will no longer download music from sites I do not trust.