Here's the fix to your problem. It's strange, but it works 100% of the time.
- Logon as any administrator level user (if you are using a standard user and elevating for updates)
- Run Wordpad. (Not Notepad because Windows autosaves notepad files)
- Type some random characters in the Wordpad
- Restart the computer but when it prompts to shutdown Wordpad, say no
- That will clear the "reboot" flag and you can run QB
