gemam03,
A few people have had this happen over the last couple of days. Maybe there's a new virus around? I'd run an AV scan ASAP & see if anything turns up. It might be worthwhile scanning for spy/adware too

Always make sure that you're using a good AV program. Keep it updated & use it to scan downloaded files before opening them! There are links here to help sites (point 5) if necessary.
WARNING: Viruses on the network you should be aware of
Within that thread you'll also find helpful info & links to security tools.