cpu overheating?

[Nauglamir]

I have a pc with a pentium 4 on an asus motherboard. I have a 400W power supply and the case has 2 fans. A few days ago, upon startup, the computer just shut off a few seconds into booting. i tried booting a couple times and noticed that it would only last a second or too now so i figured it was either the power supply or overheating. I had another brand new power supply laying around so i swapped them and still nothing. so i ordered some thermal grease because the stuff on the heatsink looked kinda old. still nothing. the heatsink fan seems to be working fine. i cannot figure out what is wrong with it. please help

 

[Elbatrop1]

Did it ever get so far as to give you any POST beeps? Can you get into CMOS setup? Does anything get displayed on your monitor?

 

[Nauglamir]

No beeps. If it hasnt been started up for a while, i can see the Asus screen load. but after 1 or 2 tries, it shuts off almost immediately.

Is CMOS the same as BIOS? and if not, how do i try that. (and is 5 seconds enough time to get in)

 

[Elbatrop1]

It doesn't seem to be overheating to me.

Try the following:
1) Re-seat your vid card.
2) Re-seat your memory.
3) Try different combos of RAM in different slots.

 

[Nitestick]

i think your motherboard may be failing based on the inconsistencies.

 

[mesa]

Have you installed any new hardware on your system lately?

 

[Nauglamir]

Tried swapping the ram chips then moving them to the 2 empty slots, and i had already removed and reinserted the vid card when i reapplied the thermal grease. I have not installed any new hardware for over a year. AS far as the motherboard goes, I do not see any capacitors that are blown or overheated (the usual culprit when we had a comp shutting off in my vo-tech class)

 

[Nauglamir]

I'm convinced its not overheating now. I opened both sides of the case and put a window fan next to it pulling air out and it does the same exact thing. i tried booting with any ram and without and graphics card and both times it still turns off at the same point.

So now for my new task.. new motherboard. Can anyone recommend a good board for a pentium 4 and a geforce 5?

Here are my case specs:

MODEL GUARDIAN SERIES
CASE TYPE MID TOWER FULL SIZE STEEL CHASSIS
DIMENSIONS (W x H x D) 200X430X451 mm
COOLING SYSTEM FRONT, 1 X 80 MM (Not Included)
REAR, 1 X 80 MM
SIDE PANEL, 1 X 80 MM
DRIVE BAYS 10 DRIVE BAYS
5 EXTERNAL 5.25" DRIVE BAYS
2 EXTERNAL 3.5 " DRIVE BAYS
3 INTERNAL 3.5" DRIVE BAYS
MATERIAL(S) SECC STEEL CHASSIS
EXPANSION SLOTS 7
POWER SUPPLY 400 WATT PS2 ATX 12V ( OPTIONAL )
WEIGHT 7.1 KGS (W/O Power)
MOTHERBOARD SUPPORT MOTHERBOARDS: ATX, MICRO-ATX, BABY AT

 

[Elbatrop1]

Are you currently using a socket 478 CPU/mobo with AGP?

 

[Nauglamir]

That is correct. The board i have now is the ASUS P4P800 SE.