Microsoft's malicious software removal tool, which is available monthly as
part of the critical security patch package, specifically targets rootkits,
among others.
http://www.microsoft.com/security/malwareremove/families.mspx
There are also two available without cost (for the moment) rootkit detection
programs:
Sysinternals Rootkitrevealer, and f-secure's blacklight.
Google on those names for download locations. You may need to stop Windows
Defenders RTP to get Rootkitrevealer to run--not sure.
In terms of the cleaning and removal end, I think this is largely an art,
and that the best advice is to back up your data and reformat and reinstall.