These are adware and not really something that an anti-virus specialises in there are a number of anti-adware/spyware programs that are better at protecting from this adware/browser hijacking of your startpage.

If you haven’t already got this software (freeware), download, install, update and run it.

  1. Ad-Aware
  2. Spybot Search and Destroy
  3. Spywareblaster Don’t install this until you are clean.

Also look at this ToolbarCop http://www.snapfiles.com/get/toolbarcop.html