Word 2007 (winword.exe) won't open, no gui, process dies quickly

So I had a user report that they were having problems opening any office programs. They weren't being shown a GUI and when I checked the Task Manager I could see the process flash up for a few seconds then die. Running winword /a manually had the same effect. So I started troubleshooting:

1. Logged on as a different user - worked fine
2. Rebuilt the user's profile - still not working
3. Tried removing various Office registry keys as suggested on some web sites. - no change
4. Reinstalled office 2007 completely - no change.
5. Started using brain, downloaded Process Monitor from the old sysinternals site.
http://technet.microsoft.com/en-us/sysinternals/bb896653.aspx

I started the capture, tried to open word, then stopped the capture. I then set the Filter to show Process Name - winword.exe and then went down the list. And then noticed about a hundred errors related to opening this one registry key.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UserData\S-1-5-21-632034446-1996701954-922709458-10172\Components

(Note: On your computer, the SID will be different). It had some weird file in it with rgb in the name so I backed up the key and then ripped out the SID entry completely. And then Voila, I was once again able to open office applications as that user.