Excel totaly disappeared from my computer
 

I did a Microsoft update last night and today 2003 Professional Excel is
gone, when I try to open the workbook here is the error:

The feature you are trying to is on a network resource that is unavailable.
Click OK or try again, or enter an alternate path to folder containing
PRO11.MSl in the box below.

I tried everywhere and I cannot find PRO11. MSl or the installer files on my
PC, I lost the original disc so I cannot reinstall. Any thoughts? Is the new
update, messing with any other people's programs?

The rest of my office programs work.