Computer not responding after pushing the power button

[ignhelper]

Today, I just upgrade my computer, everything is different, except for my internal hard disk. I also bought a keyboard. I was able to have my computer up and running, and was installing some games, namely Battlefield 3, GTAIV, Arma 2, Arma operation arrowhead. Everything had gone smoothly. I only encountered error in directx not installing, but it was successful afterwards. But I had to update BF3, so I ran the repair button. And a while afterwards, I slotted in the Arma 2 disk. Nothing happened. Afterwards, I unplugged the old keyboard and installed the new one. I also unplugged another old mouse(My old computer had 2 mouse connected, but some error forced it to run on 2 mouse). And when I tried moving/typing, my computer hanged. I decided to restart by pushing the power button and on it again. But this time, it doesn't respond, the monitor keep showing 'analog, digital, analog, digital etc.

But somehow, the CD tray works, the fan works, and it lights up. I'm wondering if its a CPU problem or monitor problem. Previously, on my old computer, I could check whether it works as it always start up with a sound, and my num lock, scroll lock and caps lock all lighting up at the same time. If it didn't light up or I couldn't get it to light up by pressing afterwards, it tells me that its fucked. So now, there is no sound, or confirmation of the locks lighting up, I cannot find out what's wrong. And the old computer goes by 1 long beep, followed by 3 short beeps. Banging does the work.

Previously, to fix it, I had to bang the case several times after pushing the power button. So now, since its a new one, I'm afraid of damaging it.

If needed, I can list all the stuff I downloaded.

Please respond. Thanks.

[paulwid]

Ya Please list i would say make sure u installed your motherboard drivers all of them and correctly, as far as the power button maybe one of the leads came loose from your motherboard in the violent storm of rage lol
can u list specs?
did u build it ?
and what programs u installed (not as important)