my first guess would be that your IDE drivers are faulty.. get to dells site and download the latest version..
I suppose it could possibly be a power issue depending on the age of the original system.. sounds like the Vid Card and CD/DVD drives are non standard for a 1 gig dell.. the system probably only has a 200/250 watt PSU unless that was upgraded with the rest...
few more details about system spec would be useful pls

