Yep, I've been a victim of this and its crept in and wipped the boot sector.
Being a my laptop was a prize winner it didn't come with a XP disc but only the software loaded and sticker/serial no underneath!!
Tried re-loading another copy and its got worse, first it didn't find the second copies boot sector, then the drive failed altogether and the machine wont see it!!!
I had Avast and whatever PC world supply with the machine anti-virus software, it got by all them, must be one of those hundreds of **** emails you get everyday!!
I didn't save my email contacts either, which has caused the biggest problem.... tried saving a number of times, but failed!!!
Be careful, I'm gonna spend xmas re-loading a new drive with all my software and a external drive for data
Andy