Browser Hi-jack
Hi witchymand,
What you are suffering from is a "Browser Hi-jack" ( not to be confused with a "Modem Hi-jack".
Its not generally appreciated but the standard anitvirus products Norton McAfee dont protect you against this type of browser hijack.
Following the advice in the clean pc post will prevent re-infestation. (spybot, adaware, using alternative browsers such as mozilla etc). Always make sure that the versions you are using are the most recent edition. (ie download first and then check for updates)
Following the advice given by previous posters re CWShredder should clear the current infection. I used CWShredder to clear something similar in the Spring.
Be careful, before you download and run any "cure" you find by googling. Some of the so called "cures" are worse than the original condition.
ajapale