Somehow when I've installed Google Toolbar on IE7 in xp another toolbar has appeared beneath the other usual one called GoogleCustomSearch. I've done a google search but no answers. There must be a way to just uninstall that one. Any ideas?
Have you checked the plug-ins for IE to see if there is a GoogleCustomSearch that is enabled? Try disable if there is.
CustomSearch should be used by webpage designers to include a search facility on their page. Are you getting it on a Google page or some other page. If so can you post the URL of the page so we can see if it's there.
A Google search for "remove googlecustomsearch" shows up some responses where people have suspected a virus. Sysdata.exe. Probably not your cause but have you scanned for virus infection recently?