My Dell CPi D266XT will not power up. The light on the power cord is flashing green. When I push the power button nothing happens. None of the lights flicker like it's even trying to come on.

check the power supply (smps)
check the CMOS battery
check the motherboard

if you have installed a new hardware, that might be the cause. specially if it is a video card. The wattage of your power supply might not be enough to run the computer. try to remove newly installed hardware such as video card. If there is none, you may try to remove the power for the hard drive and the dvd drive and check if it will turn on. Just bood in to bios..

if that works, then it definitely is the power supply. it cant provide sufficient power to your equipment..

hope that works.

regards.

Try turning it on without the battery and the power cord connected

most likely a bad power supply or motherboard. Replace the power supply 1st

Why did you buy a new motherboard? Could be your processor!!

It maybe the power adaptor is loose on the motherboard. Push the cord in and rotate it and continuously push the power button if it starts that is your problrm. You can temporarily fix it with tape once you discover where the cord wants to be or you can use a clamp.

check horizontal o/p&osc

Next time you reset, check both the monitor settings and your BIOS settings for wake up

if its the battery with a press button that lights up 5 green lights.. if u hold it for about 6 seconds it should light up all or some in a row like 000.. ( depends on charge it has) after 6 seconds none should flash , they should turn off . if any do flash or led green are missing in between its likely a bad battery.

Either the new power supply you purchased is not functioning correctly. But, assuming it is now that you are getting some form of power to your PC, it is very likely the motherboard. Whatever fried your old power supply (or it could have just been the power supply itself) most likely fried your motherboard in the process. Probably not the CPU since the MB can't even post.