Unable to launch excel

After talking to a microsoft technician and reloading
windows xp (I couldn't do a system restore), I did all my
windows updates, etc. I realized my excel wouldn't
launch though all my other office pro applications are
okay.
I get windows installer then saying there is a problem
with the shortcut and the patch package could not be
opened. I tried doing a repair thru "add/remove programs"
but when I inserted my office pro cd, I get the same
message that the patch package couldnt be opened. (so my
cd seems to be useless right now).
I also tried to download office updates but got an error
message; reasons may be windows installer patch files
(.msp) from previous updates are missing and the other
reasons were not valid such as administrator authority
which I have.
Please help,
Thanks.