I've just spent some considerable time and mental effort clearing some malware out of my computer. In case you're not familiar with the term, malware refers to any software with malicious intent, such as a virus, trojan or worm. This particular nasty diverted my Google search results to various dodgy websites, dedicated to shopping, gambling and/or attempting to deliver more malware. The infection was not detected by any of the anti-malware tools I tried (Symantec, Kaspersky, AVG, PC Tools, Malwarebytes, Spybot Search & Destroy).

In the end, I disabled it by manually editing the registry. Many thanks to the people at the various tech forums (see links below) for the information necessary to make the repairs. I had to visit these forums from a spare (uninfected) computer because the malware disabled access to these sites.

One of the many things I learned during my battle with the forces of darkness was a new word: riskware. Apparently, this refers to software that is not written with malicious intent but which can readily be exploited by malware to achieve its nefarious aims.

Technical Forums dealing with malware

http://www.windowsbbs.com/malware-virus-removal/
http://forums.extremeoverclocking.com/
http://www.bleepingcomputer.com/forums/