This is a compaq with shared video.
The computer will turn on and show the compaq splash screen, but then just goes black. Monitor power indicator still stays green.
I was able to boot a diagnostics CD. The display worked fine during this. Ran test and it showed no hardware errors.
I tried to boot a windows xp installation disk and it again gave me no display after the "setup is inspecting your computer's hardware configuration" screen.
Tried a pci video card and got exactly the same problems.