I did find this as a way to force uninstall the old IE9
1.Locate the installer you used to install Internet Explorer 9 or download a new copy from Microsoft. (This procedure might not work if you use a different version than the one installed.)
2.Go to Start > All Programs > Accessories > Command Prompt.
3.Drag and drop the installer in the black box that appears and the path to it will automatically be entered to the console. (You can also cd to the location and enter the executable if you're familiar with the Windows console shell.)
4.Add a space and the following to the command line: /X:c:\ie9\
5.Now, type c:\ie9\ie9-win7.msu /uninstall and press Enter.
Windows Installer should now attempt to uninstall Internet Explorer. Once you are done, you can safely delete the c:\ie9 directory.