IP Autoconfiguration

We have an HP Compaq PC and What gives when you can only obtain an autoconfiguration address in windows xp.. this pc is a hp compaq with an on board broadcom nic..we have connected it to a different router/network same thing ..we tried everything we could think of short of a system restore going back 2 weeks.. we installed another nic in the pci slot..same thing .we get link lights and all but no ip from the router ..even staticly configured ip will not connect to the internet .. tried firefox and IE … PLEASE HELP!