Old PC won't display anything on any monitors after switching the HDD

Gave my old build to my brother, and he bought a new monitor to use with it, and whenever I turn the monitor and computer on the computer fans / power light start up, but the monitor says no signal

I tried using 2 different monitors on my brothers computer and thy didn't work either

I also tried removing the GPU and plugging a monitor into the on board graphics and that didn't work either

Any ideas on how I could fix this?

Is there only 1 HDD in the computer?

(stupid) Is the power plugged in?

The Motherboard could be broken, specs would be helpful

yeah power is pluged in, like i said the fans and lights come on on the computer

Only one HDD in it now, but I was using it with just that one HDD in it and it booted fine

MOBO is an M2N8-AM PLUS

How old is the board and how big is the HDD?  maybe the BIOS can't detect the drive because it is too large, does anything happen if you take the HDD out?  If it is an IDE hard drive is the cable plugged in the right way it wasn't forced in upside down was it?

3 year old board, haven't tried taking ths HDD out, is that worth a shot?

I'm pretty sure the cable is in properly, even if it wasn't wouldn't the computer still go to BIOS?

Definitely worth a shot, also try to re-seat the ram while you are there for good measure.

Also make sure the 4/8 pin motherboard connector is plugged in.

ok, should I try using the old HDD or just take the one that is in it out?

No hard drive at all just to see if it goes into BIOS, make sure to re-seat the ram as well(power supply unpluged).

it worked! Resetting the ram fixed it! Thanks

also, want a copy of dota 2 on steam? I have a few extra.

No thank you good sir, im glad it worked out, take care and have fun!

ok then, thanks

Id like a copy of Dota 2