its a worm that travels through certain ports, you dont even have to open any site, thats why it is spreading like wildfire.
http://securityresponse.symantec.com...oval.tool.html
there is a fix. Use it, then update your windows all the way, there should be a patch preventing it from coming back. I got hit with it, and it was making my computer have some error every time i get on the interenet. But that fix there fixed it good. Do it soon too, the worm is supposed to be "activated" on Saturday, it will send Ddos attacks or something.