I had an asus P4S800 MX motherboard and power supply and I think I have everything setup the way it is supposed to be. The power light is on the motherboard, the monitor and keyboard are plugged in, and when I try to power up, the fan goes but that is it. Did I do something wrong? (I'm typing this out on my laptop, otherwise I would have no computer)

Hello brother..you must replace your motherboard! the problem with this asus series led consumers to panic. P4s800-mx boards are sensitive on power surges..this boards i think did'nt pass from power test tolerance. they can't withstand abrubt power changes. even the green light onboard indicates power presense and the proccessor's fan is working, believe me.that is already totally dead, even if you try to change the power supply it will not work either unlike asus's early version like p4s533mx, p4b533, p4v533 etc...are more reliable on power changes.this is the downfall of p4s800mx..but if want to still revive it, you must have a good skills on soldering small components..p4s800mx regulators sucks and even you replace it, it will bear the same problem.i only have the chance to post this solution because i noticed that anyone seems dont have a concrete solution regarding this..i already dumped 300 units of this boards. because there is no posibilities to elongate the life of this boards you are very lucky if you still have this boards(just try to use HQ voltage regulator to protect it.) the thing is, the tiny capacitors lied accross the processor at the solder side is always malfunctioning and the power regulators(component side) always changing in value that dont sychronizing to the power needed by the board...please pass my solutions to our members for them to understand. i am a filipino and we have a wide posibilities of solving this problems we love technology and technologies are just made by us we all have the solutions.

thanks brothers.....

you can contact me on my email: [email protected]

I had a very similar problem that took some wierd playing to fix. I bought a used board, put in a compatable cpu but like you the Green light came on on the mother board fans ran but no video sync.

You don't tell me abaout the cpu invloved but here what I found. Since this MB is set to jumperless it should autodetect the CPU. In this case the previous owner must have overclocked or changed the cpu settings. I though it would auto sense. it didn't.

I tried clearing the bios etc etc. but what finally worked was. I put an old basic celeron 2.0/123/400 cpu some 333 memmory.

I reset the bios(ctrlct jumped) for 15 seconds and then set it back to default 1-2 i think. I then removed the battery and repeated the bios clear reset. When I powred up the board, just mem,cpu/heat sink and the vidio bing, the speaked I attached beeped and up she came.

REmember I tried al on this with the 3.0/512/800, which runs fine now, but not on this worked. It was only when I went back to and older cpu, this board was desighned for the older chips and may not sense some new chips correctly. Even if you didn't change the chip the bios settings could have got corrupy and now it can't sense the chip that has always been there.

It the green light is on, the mb is basically sound. If it doesn'y like the chip a red light flashes.
Hope it's not to late let me know how it works or you want to review the details.

David

Hi there,

I suggest you to change the SMPS (power supply).
Let me know how many watts power supply do you use for that board?
Contact me for any help.
Add comments for more help.

neo