FYI...most Dell reinstallation cd's have a bios checker on them to ensure that they are only installed on a Dell system. Not all of them do but most. This could be your problem, but i wouldn't rule out the HDD either. If you can get your hands on that HAXTOR tester then use it.
This might also relate to the thing they call a ...........virus.
"people in ny have a general idea of how to drive. one of the pedals goes forward the other one prevents you from dying"
I say RAM
Sober enough to know what I'm doing, drunk enough to really enjoy doing it