Yesterday, one of my PCs was attacked by the SpyDawn virus. What a total pain! It sets itself up as a free virus checker and then gives you false virus reports. The only remedy for the viruses it pretends to find is to send them money to buy the full version of SpyDawn. It also hijacks your browsers so that they all open up to the SpyDawn website and it throws a ton of pop up windows out there, too.
Luckily I was able to Google SpyDawn and find a removal tool and instructions. Apparently it doesn't do any permanent damage other than the annoyance and the attempt to extort money from you.
I wasn't able to find a reference to it on the Symantec site nor on the Microsoft site. It must be a pretty new bug.