Double clicking a PS doc launches PS, but does not open the file

I am really frustrated... Double clicking a PS doc launches PS, but does not open the file. This may seem trivial, but becomes very annoying after a few months!

I have tried trashing my prefs but it still happent - PS CS v 1 on a g5 dual gig - non intel

Thanks

See the second listing in red at the top of the main page...

Its also in the FAQs.