Have a look here and also, afterwords, maybe use one or two of the following to make sure its gone: F-Secure On Line Scan -- http://support.f-secure.com/enu/home/ols.shtml
BitDefender On Line Scan -- http://www.bitdefender.com/scan8/ie.html
A-Squared On Line Trojan Scan -- http://www.windowsecurity.com/trojanscan/
House Call Anti-Virus http://housecall.trendmicro.com/housecall/start_corp.asp All the programs mentioned are for free.

Just as an FYI, in the future, you might want to post this type of question in the virus and security forum.
Good luck,