Excel/Word crashes when right clicking

Whenever I try to highlight do the a right click on the content of a cell (EXCEL) or portion of text (WORD), the software crashes and I have to force quit.

I have never experienced this before....which is puzzling and really frustrating.

I am using Microsoft Excel/Word for Mac 2004 (11.6.4 for Excel and 11.6.3 for Word). I have tried the same manipulation with Numbers and Pages and it works fine.

Any help?

Thanks a lot.

G.