File Open and File Save do not work in Vista

Hello.

I'm using Vista Business upgraded from XP Pro SP2, and am experiencing a rather fustrating problem.

All (common dialogue) Open and Save dialogues crash their parent applications, that is to say that clicking File>Save in any programme, causes it to immediatedly and often fatally, crash. The Save / Open dialogues never appears; I've never seen the Vista Save dialogue. It seems that the 'filepicker' is broken, and my only thought is that it might be due to some left over bit of registry from XP.

Trawling google, I have seen at least a dozen people having this problem with Vista, and no satisfactory solutions (certainly not from Microsoft or their 'throw a coin in the well' Vista problem report philosophy). The five possible solutions I've seen suggested are :

1. Remove ShellIcons key from registry (I don't have a ShellIcons key)
2. Remove broken shortcuts from the desktop (my desktop is empty)
3. Set program defaults to Microsoft Default (no effect)
4. Virus & adware scan (done)
5. Reformat and start again, bluffing the upgrade disk on the way. (I'd rather not)

Has anyone resolved this problem in another way? Any ideas, which of filepicker's dependencies could be broken?

Any help at all would be appreciated!

Jonathan

ps. Sorry if this problem has been mentioned before, but as far as I can tell little light has been shed on it and I'm sure as time goes on more and more people will encounter it.