Windows server 2003, to Windows XP

My girlfriend got a Dell XPS M1710, that originally was delivered with Windows XP os, it got the Windows XP Professional reg. key sticker underneath.
Her brother in law, took it home when new, and installed Windows server 2003, because he hates Microsoft, and XP.
Is there somewhere I can download the XP professional os, and register it with the original key?
Seems to me that drivers for cameras, and on board hardware, is difficult to find, for Server 2003!
I would be very grateful for any help, thoughts on this …. problem,..project

Thanks in advance
Regards St?le Johansen