Of course this would mean that your computer 
would have to be tragetted out of how ever many 
zillion computers had it, that the hacker 
would've had to know what they were doing and 
have -very- speficic tools, manage to intercept 
the right information -and- know what that 
information was being used for to exploit it I'd 
say among a whole range of other incredibly 
unlikely circumstances :D so it sounds almost 
astronomically unlikely... But I'd be lying if I 
said I was a security expert myself!

I had the blaster worm for about 16 hours on my 
own PC, 8 of which it was online for and I never 
bothered to reset anything after I'd cleaned it, 
personally!