Don't listen to all of the complicated stuff you will read. Go to YouTube and search for MD Tech instructions for fixing Windows Installer. You can search for 'fix Windows Installer' and choose the MD Tech video (the best one).
Watch video and follow directions. Then you will probably found that the Intuit update is still running from your attempt to update. Open Windows Task Manager and end the Intuit update.
This should fix your problem beautifully. Don't spend hours with tech support; they didn't come close to a solution for me.
