Most of these detectors require quite a bit of technical skill to interpret the results but one of the simplest to use and most effective is also free. It's called BlackLight [1] and is currently available as a free beta from F-Secure until the 1st of October 2005. I suggest everyone download this product and scan their PC. The chances of you being infected are small but for five minutes work it's not worth taking the risk. BlackLight will detect most rootkits missed by AV scanners but can still be fooled by state-of-the-art rootkits like Hacker Defender. To detect this and a few other insidious rootkits, you need heavier artillery. Currently the biggest gun in the rootkit detection war is a free Chinese product called IceSword [2]. It will reveal absolutely everything running on your PC. Usage, however, requires considerable skill together with the patience to work out the program which is currently only documented in Chinese. In the hands of an expert, its an amazing tool.
[1]
http://www.f-secure.com/blacklight/cure.shtml Windows 2000 and later, 911KB.
[2]
http://www.Xfocus.net/tools/200505/1032.html slow Chinese site, 1.5MB[