You installed XP, but no word about video, motherboard and other drivers.
Finish the driver installs.
Ive got a Dell Inspiron 2600 laptop. Its got a Intel Celeron 1.3GHz processor and 256MB of RAM. It was running on Windows XP Home but it was full of crap and running slow so I deleted everything and indtalled Windows XP Pro. Now it won't let me select a video resolution above 640