Grisoft today announced its free AVG Anti-rootkit software for Windows XP and 2000, designed to detect and delete the malicious kits that try to hide malware on a PC.
If a virus with rootkit functionality made its way onto your computer, its files and processes would likely be hidden in Explorer, the Task Manager, and other tools. The company's AVG Anti-Virus software is also available in a free version.
The AVG Anti-rootkit download is a tiny 414kb, and installed quickly. Its straightforward, no-frills interface allows a regular search and an in-depth search, though it doesn't tell you the difference.

A standard scan took 12 minutes on my work PC, while the in-depth search took just over an hour. Neither scan turned up any rootkits, thankfully.
If you think you might have hidden malware on your sytem, it's a good idea to run multiple rootkit detectors. Much like anti-spyware, no one program catches everything. Some antivirus software attempts to detect rootkits; others don't.
We looked at a number of other free rootkit detectors last June, including RootkitRevealer, IceSword, and GMER.