Mary,
I have not looked up on your PC's specs, but, on most newer PCs -
thy have a built-in feature whereby an "image" of the XP installation, as
it was when it left the factory, is written to a hidden part of your
hard-drive.
This can then be restored to the main [visible] part of your hard-drive
[C:\] usually, by pressing F10 - BEFORE Windows loads.
i.e.; After you press the "power on" button, but *before* the "Windows XP
loading..." screens.
Having said that it is usually F10, it may be F9 or some other F-key, but
just which - there should be a message displayed (right after you press the
"power on" button) something similar to :
"Press F9 for recovery options." at the bottom of a screen together with
the PC manufacturer's logo on it...
Alternatively, writing to the PC manufacturer may provide you with a
replacement disk for a minimal administration fee.
The place to start, I would say, would be to peruse your PC manufacturer's
website for more information.
==
Cheers, Tim Meddick, Peckham, London.