Sean, I feel your pain, at the begining of last year I ran my "ad aware" program, it asked me to update my definitions (like I had done many times before), as soon as I did, I knew something was wrong (2 porn pop ups on my explorer window). I lost everything on that computer. Now the new story, that computer was my last windows machine that I had at the house, it was a dell that I basicaly paid all of my bills with and ran my quicken program with, I have been slowly switching over to macs over the last 5 years, but I did not want to switch over all of the information manually (a lot of account numbers, addresses, etc.), plus I just wanted to have a windows machine for backup. Fast forward to now, I have totaly switched over, none of the 5 macs we have in the house (my 17" powerbook, my imac, wifes imac, daughter's imac, and other daughters ibook) have any virus protection, nor have we had any problems as of yet, the computers come with a multitude of programs (website software, photo/music/movie/dvd software, etc.), and are cross platform compatible, I could go on and on, but just thought it may be something you would want to consider, especially in todays day and age. Good luck with the reformat as well!
Greg