Excel 2007 on Windows 7 - Problem with ribbons

I bought a pc with Windows 7 that has worked fine with Word (office 2007). However, when I save a file with Excel 2007 and then call it up, the ribbon no longer works (I click on the various commands and ribbons don't pop up). Likewise, I cannot make cell entries or try operations like sorting. However, the program has not frozen since I can click on the various worksheets on the bottom. Is this an Excel or Windows problem and what is the solution.

Hello cengelhart and welcome to Seven Forums.

Try running the Office 2007 diagnostics checks. Even if the diagnostics doesn't show any issues, next run the repair function. Please post back if this helped or not.

How to install the individual 2007 Office features or to repair the installed 2007 Office programs

I checked for updates, tried the repair option on the disck, and then re-installed using the disk with no success.