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If you can boot into safe mode I would do that.

Malwarebytes antimalware is an excellent free program as mentioned above and they have just released an Antirootkit program as well although in beta release

http://www.malwarebytes.org/products/mbar/

I am also a fan of DR Web Cureit Free Antivirus

http://free.drweb.com/

Hiren's Boot CD is probably one of the most comprehensive boot malware CDs available

http://www.hiren.info/pages/bootcd