Thank you for your question, my name is Richard.
This can be due to corruption in either the registry or hard drive and I want to rule this out first please.
Download CC Cleaner (free) from hereCC Cleaner
(Click Download Latest Version on the top right)
Run it and let it scan and repair your registry.
Once done, restart the computer
Click Start, All Programs, Accessories, right click on Command Prompt and select Run As Administrator.
A black window will open.
Type in it
press enter and when it has completed, type in
It will complain the Volume is in use and to run on restart. Say YES and restart the computer
Than try to open Office and let me know please if you still have the problem.