Use the working monitor and boot the OS to Safe Mode. What happens?
I am working on a Compaq monitor that does not come up. The power light is on, but the screen is dark. The monitor belongs to a Compaq Presario, 733 mhz, 128 mbs ram, 15 gb hard drive. I put an older Packard Bell monitor on the Compaq and it goes into post and then pops off before getting to the desktop.
I put the Compaq monitor on my Gateway and it will not come up on that either, same thing, power light is lit but will not even run post.
I was thinking the monitor is defective at first but now I think that I may be dealing with a defective power supply also. The Compaq's drive lights do come on however.