1. I would insert your Office program CD and you should get a repair option instead of the normal install Screen. Run the Repair option and see if that helps you out.
2. If 1. doesn’t help you look and see if you have IOBit 360 installed and if you do uninstall it. Seems that this program causes more problems for Office users than good.
3. If none of the above work take a look at the following link to change you Virtual Memory.http://www.internetfixes.com/blog/?p=276
Please respond and let us know the status of the issue.
Gary - InternetFixes Support.