You very well may have a failed motherboard or CPU rather than power supply. Although a standard ATX power supply will not fit inside your case, the connectors are identical and one can be used for troubleshooting.

First, check capacitors on motherboard for signs of swelling or leakage. Pay special attention to those near CPU socket. Here's a link with more information:
http://www.badcaps.net/pages.php?vid=5

If caps look OK, connect another power supply of higher wattage for testing. Borrow one from a friend if you can.

Clean CPU fan and heat sink as previously suggested.

Unless there are physical signs, it is very difficult to differentiate between a failed motherboard and a failed CPU. Given the symptoms you described, I'd lean heavily toward the motherboard.

Here's a good quality replacement power supply if needed:
http://www.newegg.com/Product/Produc...82E16817103507

It is actually an SFX form factor although many call it a uATX.

1:is thermal compound on CPU heatsink?
2: did you clean the fan on the heatsink?
3: does the fan on the heatsink turn?
4: does the internal fan on the case turn?
5: And important > did you re-enable the ON BOARD VIDEO in BIOS after removing the ATI Card?

And yes - a 200 watt power supply on a P4 with a High Powered graphics card could keep the system from starting or causing other issues.

The ATI All-in-Wonder is now a generic name, the models graduated and consume a bit more power than those 5 years ago. Especially if it has 3d and Radeon 8500 chipset.


Why do you think he works at FRY's??? Maybe he thought it was an improvement from fries at McDonalds...

To get into the BIOS on a HP as it boots hit F1. Are you hearing any beeps as it boots?
If the system has been getting that hot may have already damaged the CPU. Pull the heat sink and fan clean the dust from them. If you have a local computer repair shop close go there and ask them for a little thermal compound. when you put it on if the top of the CPU has a small rectangle on it put about the size of one piece of rice. If it is flat and solid spread it even either with a credit card or razor blade. while doing this take the battery out it will reset the BIOS take out the video card and use the onboard video. unhook everything but the HDD plug in your 20\24 pin whichever you have and if it has the P4 4 pin plug it in. turn on the PC listen for beep codes, If no beeps then chances are you CPU got overheated shorted and took the motherboard down with it.

Re PSU form factors:

Realized that HP has used both uATX and SFX PSUs in their PCs. If PSU has 3 mounting screw holes it is SFX and uATX if it has 4 mounting screw holes. uATX is same as ATX except shorter.