I think it's F12 at boot to run the diagnostics (using the D800 right now), have you tried it?

I've tried that, although I'm not sure it worked. After several tests (I think the final test is the VGA test) the screen goes white
and then I get a sequence of beeps and keyboard lights. This seems to go on until I hit escape. Does anyone know if this is the last test?
I also ran a microsoft memory tester (http://oca.microsoft.com/en/windiag.asp) which passed ok. Its quite good, even writes a bootable CD.

Time to call Dell.

Ok, thanks for the help

Stephen

NP, let us know what piece of hardware died.

I ran through the dell diagnostic test using an external monitor so I could get past the "white out" (Dell support suggestion) and I could see it was failing on an LCD inverter test, although I've not had any problems with the LCD so I'm not sure what that part actually does. I then carried on through all the tests and it failed on the IDE test, seems my hard disk has some bad sectors. I've fed this info back to dell 3 days ago but they've not responded so I guess I'll have to chase them. They have a pretty poor customer service, which is a shame as there products are pretty good (when they work!).

Their customer support used to be good, but since they've switched to India for support, I've heard nothing but complaints.

Sad to hear about the support but it seems very common, it has gone way down hill!

As for the inverter it adjusts the power so that it is usable for the LCD.