Go here and get the latest BIOS update also.

http://support.asus.com/download/download.aspx?SLanguage=en-us&model=P4P800-E%20Deluxe

Most of the time the power leads are marked on the power switch and HDD led and such.also on the mother board normally at the bottom right side.if you put them in upside down the system won't start...

Check the jumpers on the Hard drive make sure all you ribbon connectors are right, red wire to pin one.is the system coming on if so make sure you video cables are connected securely.going to a...

I had one here in the shop that did the same thing.the power supply was bad so i took one of my known good ones off the shelf and hooked to it did the same thing.come to find out it was the memory...

Sounds like the battery is bad to me also.

well some you may not need if it is a P4 power supply and your motherboard isn't the 4 pin connector you won't.the 20/24 pin is pretty obvious the rest is for power to your HDD and CD/DVD drives they...

HMMMM.

Here is a flow chart for power supplies.

http://www.fonerbooks.com/power.htm

I use a Power Supply tester to test them but this chart may help you.

Go to screen saver then power and see af hibernate and turn monior off and such is on.

if not that you may try taking out the heat sink and cpu clean off the old thermal compound and put new on...