If you are running Windows XP, be careful. I haven't figured out where the vulnerability lies exactly....lol...you're running XP the OS is the vulnerability. There is a new rootkit (tdl-3) that I suspect comes from infected wordpress sites via drive-by-download. This is a very well written rootkit and it is constantly morphing. If you go to a wordpress site that ask you to download a video codec to view the video on that blog, don't bother. I'n the meantime keep that data backed up so you have something to go back to when I have to reformat your machine.
It is time to get away from XP. It has earned it's retirement the same as your tired-ass linksys 54g router has. If you prefer the ostrich approach to security, that ass will be had.