No respnse from laptop

A co-worker gave me his laptop to play with and see if I can get it working and I'm at a loss so maybe someone here can help me. When I push the start button it powers up but does nothing else, the fan is blowing and the power lights are on but nothing else. The hdd light flashes for a second but thats it, the screen stays black and nothing else happens.

I've tried to get into safe mode but get no response, I've tried to boot to the windows cd but get no response so tried replacing some hardware. I started with the hdd and nothing, then the ram, still nothing, then both and still nothing. Any thoughts on what else to try?

Clear or reflash the bios perhaps?

Have you tried connecting it to an external monitor? There could be backlight or TFT errors. If this doesn't help, it gets harder to diagnose, as it could be the video chipset or other planar mounted components.

I did try hooking it up to a crt I have laying around and still nothing and I can't reset the BIOS because it wont even post.

I had a laptop that would not boot because the battery was fried, When i plugged it in without the battery in it booted fine.

got a new battery and all was fine

This one does have a toasted battery but if I take it out I get no response from the buttons. I'll work on it that avenue though, thanks for the info.

EDIT: I got it to respond with no battery but still the same. I will start over with no battery in.