Right, having installed the Office 2007 beta I uninstalled it as it was delivering all my emails without text, which seems to be a known problem.
And it's broken my Office 12 install. I've uninstalled and reinstalled it a couple of times and Outlook won't work: it's unable to read toolbar data.
Each time I uninstall and reinstall it, it retrieves all my data, which on this occasion I don't want it to do - I want a clean, fresh start as something, probably in the .pst file, has been corrupted.
I've also tried a repair reinstall and that hasn't worked, either.