I recently installed a new PSU and graphics card done correctly, wired up good got it running but I forgot to power my disk drive so I turned it off wired the disk drive up and now there's no signal I've tried taking one RAM out then powering it, nothing also tried unplugging everything holding the power button then putting it all back together, still nothing and have ran out of ideas, anyone else got some?
Is the computer showing any signs of life?
Is the graphics card one that needs power direct from the PSU, and is it connected?
Have you tried booting it with the disc drive unwired again?
What PSU, Graphics card, and motherboard are you using? - and how many drives are connected?
At this stage my guess is (and it is only a guess) that the power supply is not big enough. I am being premature here, but it might be worth checking.