You could try setting up a VM using VirtualBox or other free virtualization software and running Excel XP there using Windows XP or Windows 7. Of course you will need a copy of Win XP or 7 in order to do that.
Another possible solution is to install LibreOffice which is a free, open source office suite that can read/write Excel, Word, Power Point, etc... documents.
You can't really blame MS, Excel XP is really ancient (2002).