I have a Dimension XPS T500 with a problem. I had to reformat the HD so I could reinstall Win 2000. After the reformat when I power on the computer there's a brief message on the screen something about NVIDIA and then the screen goes to the DELL logo and just stays there. I can't F2 into Setup. The "D" light is yellow and the computer won't read the Win 2000 set up floppy. As a matter of fact the computer doesn't seem to be reading the A drive at all. I'm stuck. Help!!!
A green, green, green, yellow diagnostic error code is kind of a catch-all one and really doesn't point to one particular problem. The problem could range from a simple NVRAM corruption to a failed hard drive or something more serious. The best you can do is try the trouble-shooting steps I have listed below until you find the device that is preventing the system from booting.
Try clearing the NVRAM (CMOS) to see if it resolves the boot problem. Possibly the information stored in the NVRAM (CMOS) became corrupted which is not uncommon. With the machine unplugged from the wall remove the battery from the motherboard. Then with the machine still unplugged press the On button for several seconds to dissipate any remaining electrical charge on the motherboard. Then re-install the battery, plug the machine back into the wall and see if it will boot normally. Depending on the age of the system you might try installing a new battery when clearing the NVRAM. A failed battery can cause a variety of boot up problems. A new 3-Volt, CR2032, coin cell battery can be purchased for around $3 (US) and is available at any Radio Shack, computer stores and most discount stores.
If the machine still fails to boot then strip the motherboard down to the bare minimum. By bare minimum I mean remove all expansion cards, disconnect all drives and leave just the processor, memory and graphics card in the machine after reseating them. If the computer boots this way then start connecting each device one at a time until the no boot scenario returns. This would then indicate which device has failed and is causing the problem. Also try booting the system without the keyboard, mouse or any other device plugged into the rear of the system. If you have more than one memory module installed then try booting with only one and then swap them around and try again. If you only have one memory module then try booting without any memory modules installed. If you have another graphics card available then also try swapping that. If this procedure doesn't resolve the problem then you maybe looking at a situation where the motherboard has failed.