I had this shit on one of my PCs, it's called 'iframer heur' . even if you have a firewall the virus spreads.
if you're using cuteftp or filezilla it steals your ftp passwords and puts those iframes on every page that has 'index' in the filename (it makes it recursively, on all folders)
right now the only antivirus that detects it is Kasperksy but there's no antivirus that cures an infected computer.
the solution is to reinstall windows... or better: buy a mac
