Office XP - Can't open a Word or Excel file

[Mickey]

I am running Office XP on Win XP- I Can't open a Word or
Excel file. If i try to open any of my existing excel
files i get an error saying 'unable to read file"..

If i open any existing word file, for example a file
called Airmail.doc, i get a message saying "The file
Airmail is not available'

any suggestions would be helpful..I started having these
probelms after reinstalling Office XP.

Thanks

Mickey