JSI Tip 9095. Freeware RootKitRevealer detects persistent rootkits (malware).

The RootKitRevealer page contains the following introduction:

RootkitRevealer is an advanced root kit detection utility. It runs on Windows NT
4 and higher and its output lists Registry and file system API discrepancies that
may indicate the presence of a user-mode or kernel-mode rootkit. RootkitRevealer successfully detects all persistent rootkits published at www.rootkit.com, including AFX, Vanquish and HackerDefender (note: RootkitRevealer is not intended to detect rootkits like Fu that don't attempt to hide their files or registry keys).