Related (for Windows XP: IE8 search provider corruption keeps forcing Bing.com upon me?)
Windows 7, with Internet Explorer 9 and no add-ons loaded will bring up this message every time it starts:
A program on your computer has corrupted your default search provider setting for Internet Explorer.
Internet Explorer has reset this setting to your original search provider, Bing (www.bing.com).
Internet Explorer will now open Search Settings, where you can change this setting or install more search providers.
When I click OK, it brings up the Manage Addons page, and I can't do anything with the Search Providers. Looking at my thread about How to Manually edit the Search Providers in Windows Internet Explorer 9, I tried going through the registry without finding much help. Resetting IE (Tools->Internet Options->Advanced->Reset) did nothing. HiJackThis reported nothing out of the ordinary, and this occurred in Safe Mode as well.
I created a new user account, and the new account did fix it, but it is undesirable to copy all the user data over and change names. I also tried uninstalling IE9 through Installed Updates, but the same issue happened with IE8. What else can I try?