xlsx won't open with compatibility pack
 

Windows XP, Office 2003 sp3, Compatibility Pack.

We have one user who is unable to open xlsx files even though the
compatibility pack is installed. She first gets an error that says the file
type is not a recognized format. THEN the file opens in excel, but the
characters are all "garbage".

She is able to open any other 2007 file - both Word and Powerpoint are
functioning as expected. Other people can open the same files that she is
unable to. It's not limited to a particular file - no xlsx files open for
her.

She doesn't have this problem on other PC's. We haven't yet verified, but
it seems likely, that anyone else working on her PC would have the same
problem.

If at all possible we'd like to avoid a reimage.