the possibility the product key you type in REALLY is invalid. There could be a typo, or it could be a pirated copy with a fake product ID.
If it's the real Microsoft thing, and you're sure you type in the correct key as shown on the CD box, contact the vendor.
Kees
I just installed MS Office Professional 2003. When I try to open a document, the setup menu comes up asking for the product key. If I hit cancel, the program closes. If I try to put in the product key, it says it is invalid. I tried uninstalling, then reinstalling the program. It looks all right and seems to install properly, but the same message comes up when I try to open any program. Thanks for any help!!

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