Here's the fix to your problem. It's strange, but it works 100% of the time.

1. Logon as any administrator level user (if you are using a standard user and elevating for updates)
2. Run Wordpad. (Not Notepad because Windows autosaves notepad files)
3. Type some random characters in the Wordpad
4. Restart the computer but when it prompts to shutdown Wordpad, say no
5. That will clear the "reboot" flag and you can run QB