I am taking my computer back to the original installation. I have MsOffice on it, with a single use product key. If I re-install my O/S (Vista), can I use the same product key for my MsOffice, or do I need a new one?
The product key is always the same: I think that your product key is "single user", i.e. it is valid for a single installation of Microsoft Office on a single PC and not on multiple PCs.