Quicksilver 800mhz start up problem

Well here is the story,
I picked up a power mac quicksilver 800mhz from my work that has been sitting there un-used for a while along with a graphite 400mhz g4. I started up the 400mhz g4 to see if it works, it did. The quicksilver had no hard drive so I put the hard drive from the 400mhz g4 in the quicksilver to start it up. Wellll the quicksilver would not start up. It would power on the start up light, chime and then the power light would fade off. The fan is going by the power supply and the red led is on on the logic board but the HD seems like its not on and there is no video signal. I tried doing the reset cude thing and even took the bettery out of the 400mhz g4 and put it in the quicksilver and the same thing happines...there is also no power going to the keyboard or mouse...if that helps any?!

Ive been searching the web for a while and been searching multiple forums but I just can not find anything to help me...and I dont want to throw money into it if I dont know what the exact problem is.

Thanks, Phil

Try re-seating the video card (it should be in the AGP slot in the Quicksilver). If that doesn't work, try disconnecting the IDE cables on the motherboard for the hard drive and motherboard. Basically try and boot it up with ONLY the motherboard/logic board, CPU, RAM, video card, and power supply plugged in. Make sure to disconnect the power from the hard drive and CD drive as they may be causing the problem. This will help you narrow the problem down to a certain component. It sounds like you have a sour logic board or video card, but I could be wrong.