Please help with a starting problem

Hello,
I have a Compaq Presario S4214BD with a 2.4 GHz Intel Processor,512 MB DDR SDRAM memory and a 80 GB Seagate hard drive.
This is my problem-
When I try to start it up,I only get the yellow LED...no green.
The CD Rom shows that it is on but the tray will not open.
I can hear what I can only describe as beeps and clicks.The fan on the mother board tries to turn as if the computer is trying to start.Every once in a while,the green light does kick on and the fans start turning but it kicks off again.
Here is what I believe started the problem-
I had the computer and the Air Conditioner on the same circuit and the circuit tripped.I told my kids and wife to wait until I moved the computer before they tried to run it again.Of coarse that they are,they could not wait for me to move it and tried to use it anyway.After repeated circuit trips and hard shutdowns I now have a computer that will not start.