It may be a bit of overkill, but you could try OpenOffice click here it's very good at opening Microsoft files and as long as your backups aren't corrupt should access them.
As OpenOffice is fully open source, there are no license problems using it on business work.
Not sure what your problem with Office is, though it sounds like a corrupt file extension. Could the PC have been trying to access the CD backup copy from recent documents ? If the disk wasn't there, that would give it problems.