Strange happenings in Word after 2003 upgrade

After upgrading to Office 2003, a couple of strange things are happening in Word, specifically:

1) When I double click to open a Word file, Word opens, but the file won't until I open it using File/Open.
2) Once a file is open in Word, I am unable to click to select text, or use any right-click functionality.

I was having similar problems in Outlook, but that was due to using Word as the default Email editor - once I turned this off, everything seemed to work without any problem.

I have tried uninstalling and reinstalling Office, adding more permissions to the Office key in the registry (HKLM/Software/Microsoft/Office...), and I also tried adding myself as a local administrator on that machine. No luck with any of these possible solutions.

Any solutions anyone out there would be greatly appreciated! Thanks very much.