I had a user that had a corporate version of Office 2010 installed for over one month and all of a sudden it said it wasn’t activated. The company help desk worked on it for hours and hours and told her to reimage the computer.
I investigated and ran the registry fix and KMS.exe they have internally, but it didn’t work. I found that the date was one month behind. I changed the computer’s date to the current date and it was activated!!!
SUMMARY: Check the computer’s date and time.