Boot up stops at BIOS Logo.

Hello,

I bought a new Acer 22" LCD DVI monitor for my Acer T120E and wanted to put a grafic card to go with it.
The onboard card was too slow.

So I put in a Sapphire Radeon 2400 512 MB AGP card and a 500 watt power supply to support it. I also added 1G RAM to the existing 512MB. I had to disconnect the cables for front side audio jacks and CD-In cables to be able to put the grafic card in position.

I checked the Bios setting. There was no switching provision for on-board to AGP. I guessed it has automatic detection

The front side power switch stopped working for some reason. It had to be switched on from a power switch that came build onto the SMPS itself. However, I switched on the machine and it started up just fine. It detected the additional RAM and gave perfect VGA output from the Sapphire GCard

I realised that I had left out the two audio cables. So I shutdown, connected the cables and also connected the DVI cable this time disconnecting the VGA one. Then I restarted it.

Then on it wont start any more. At switch on it shows the Acer logo with ((Del - setup F12 - Bootup Menu)) written underneath and doesn't go any further. The Del or F12 keys do not work either.

I took out the memory cards and switched on. Sure enough there was a constant beep, which should mean that my MB is OK.
So I tried the pencil eraser method. Still same result.
I went back to the old power supply - Same result
Tried each memory card separately - Same result.
I took out the new Gcard and tried the onboard VGA output - Same result
I cant get into BIOS setup either.

All fans working, DVD drive responds, hard disk spins, all lights blink as usual on switchon

Cant understand what could go wrong while connecting audio cables. Please help. Thanks