cannot run, install, or remove excel 2002 on win xp

Excel and other Office apps have been running fine on this Dell laptop I
bought in '04. Then Excel stopped running. When attempt to I run it,, or
install it, or remove it I get the msg:
'Problem with Shortcut
The installation source for this product is not available. Verify that the
source exists and that you can access it.'

Note that this msg does NOT allow me to browse to show where the Excel
installation exists. It just lets me press OK.

I thought this might have to do with Office coming pre installed on this
laptop. So I called Dell, got huge runaround but then finally got to a
knowledgeable seeming tech. He told me I had to deinstall all of Office to
reinstall Excel. I was nervous about that but said I'd try it and hung up.
But when I tried to deinstall Office, I got the SAME msg.

And this time after several tries always leading to being disconnected
before reaching Dell support, I have not been able to get to their tech
support dept. At least not to anyone who can help.

Suggestions?