My computer Dell Demension 5100...old i know but i need help?

so my computer is 5 years old. sad but tru. so im trying to reinstall windows xp onto my computer and after i did a format or whatever ( not computer savy at all) basically a blue screen with a yellow loading bar that was said it was copying files. my computer restarted like it said in the steps...but now it just flashes the dell opening gui where it says dell in big blue letters on a black screen with dmension 5100 below it with f2 and f12 options in the right corner. this screen continues to flash and wont stop. i called dell and basically said **** me because of my warrantee has expired but he said i should run diagnostics which i did and it said that the drive 2: PHILIPS DVD dvd rw dvd8701 - diagnostics not supported. i was wondering if my drive is ****** or is it just my reinstall. and could anyone help me further