About a week ago Internet Explorer 9 started showing an error on startup on one of our PCs at work. This solution worked perfectly - no issues so far. Here is the compact version - we will be doing settings reset:

1. Click “Tools” (the right-most gear icon) -> Internet Options
2. Go to “Advanced” tab -> Reset…
3. Click Reset to confirm.

Note that I did not delete personal settings and it still worked.
Next startup of IE was as smooth as new.