Missing a file?
I think they are making stuff up. Still, if they did some diagnostics through you and really did determine that that is the case somehow, you can do the following:
Have your XP CD Ready, go to the Start Menu, and Run. Type:
sfc /scannow
Click OK/Press Enter.
Like I said though, I doubt it will actually work, since there isnt any reason for a missing file to really be related with this issue... but, if they think so, we can prove them wrong here.