Hello,
I have a DELL XPS/Dimension XPS Gen 4. All diagnostic lights are green (A, B, C, D)
Nvidia 6800 video card.
Pentium 4 Prescott Dt, Pentium 4 Prescott DT, 3.4GHZ, 1 MEGB, 800FSB
It is exhibiting similar behavior as in most other cases listed here (no beep, no video, all fans, drives...