Something is wacky with the file associations.
Look in the Folder Options control panel.
I have a user that uses Excel a bunch. He recieves reports and assignment sheets from other users as well. Right now, if he tries to double click on a file in an email, it will open excel but not the file. Make sense?
Same goes for a shortcut to a file. It'll open excel, but not the file. However, you can still open the file from "File > Open" option in the menu.
I've uninstalled/reinstalled, ran spyware/virus checks, rebooted, poked and tinkered and I cant figure it out.
Have you guys heard of this one?
File associations sound okay... It's opening excel. Are you sure the spreadsheet version matches the version of Excel? As in the sender sending an Excel 2007 sheet and the user having 2003/2005. (sorry, can't remember the years)
Play with it, 'til it's broke.