What is a rootkit and how do I get rid of it?

Rootkits are programs that hide themselves from the operating system (OS). Originally, these programs where meant to be used by the OS for system tuning, cleaning, etc. However, their use has been hijacked by crackers and malware writers to hide their malicious programs.

For more information see:
http://en.wikipedia.org/wiki/Rootkit
www.microsoft.com/technet/sysinternals/utilities/RootkitRevealer.mspx

There are several good programs out there to find and remove rootkits. For example, see these links for reviews by Information Week.
www.informationweek.com/showArticle.jhtml;jsessionid=QAETVUSKBLWSYQSNDLRCKHSCJUNN2JVN?articleID=197000846&queryText=rootkit
www.informationweek.com/showArticle.jhtml;jsessionid=QAETVUSKBLWSYQSNDLRCKHSCJUNN2JVN?articleID=196901062&queryText=rootkit

Some of these Windows programs are:
Rootkit Revealer: www.microsoft.com/technet/sysinternals/utilities/RootkitRevealer.mspx

Rootkit Unhooker: www.rku.xell.ru/?l=e&a=dl

IceSword: http:www.majorgeeks.com
Do a search for IceSword. Note that the help files for this program are in Chinese.

Rootkit Buster: www.trendmicro.com/download/rbuster.asp

Sophos Anti-Rootkit: www.sophos.com/products/free-tools/sophos-anti-rootkit.html

You should also note that some of these program must be installed before being run. That means that they may modify the registry. Other can be run as is.

[red]Just like for anti-spyware and anti-virus programs, it is a best practice to use several of these as one may find something another has missed.[/red]