I recently got this and I don't know how to get rid of it!
It all started when Avast! detected a virus. My computer then locked up and I had to hard reboot the system. When I logged back in, I notice a huge slowdown in startup and then this popped up. I then issued a boot time scan and deleted a good amount of worms, virus, and trojans. After logging back in from the boot scan, this still popped up with the red x on the bottom right corner telling me that XP needs to install updates to prevent viruses, blah, blah, you get the point. Random popups also come up and that's really annoying.
So I am here now, asking for help form the Avast! community.