Have a Dell Precision 670 that when turned on, cycles through WindowsXP screen, to the Dell screen, to No Signal screen, to the "We apologize..." black screen which has 25 second timer. It keeps cycling through these four screens. I have checked the processors and reseated the RAM and the PCI Card. I have tried the Safe Mode, the Safe Mode with Command Prompt, but nothing happens. Just keeps cycling through those screens. The power lights are 4 green, not blinking. H-E-L-P!