Motherboard only boots every other time.

If the fan of the processor is not spinning that means that your processor have a problem. If the CPU fan is spinning and after a second it stop that means your processor is defective

Have you checked the posibility of 512 Mb limit per slot for your motherboard? This is often at some older mobos. The manufacture page for your mobo is here check the revision you own.

Stelios.

USB is controlled by the Southbridge on the motherboard. If that chip is fried, the PC will not boot at all. These chips cannot be replaced.

or,

You can try unplugging the Front USB panel from the motherboard and see if that works.

Not the first time I have seen/heard of this. Always just seemed to short the mobo out.

Hope this offers some insight!

The mobo is in fact compatable with the core 2 duo socket 775 chips.

Where does it hang on boot? Do you get the POST?

Download windows for with no need floppy, and boots from your cd'rom

Hi, This is an old board trying to run a hungry CPU. From the symptom you describe the poor thing may be wearing out right in front of you. Anyhow, - In order of likelihood your problem(s) are probably:
1 - Defective motherboard. PC chips is well known as a maker of cheap mobos. When run even a little hot they have a short lifespan. A 3Ghz Pentium Prescott needs a lot of power. A faulty part may not always kill a session but it can ruin your life. Try running the PC underclocked at ~2Ghz. See if the prob goes away. If so, better cooling the support chips may help. Best solution is replace this old warrior with a new mobo. You will also need a new PSU & CPU if this is the problem. Except for playing games, even slow dual core CPUs will perform better than a single core unit.
2 - Bad PSU. These also wear out, especially if run hot. Best solution is new PSU. If you do this, get a modern model that will handle a mobo upgrade should that also become necessary. Many options & prices here - be careful.
3 - Bad PCI card or RAM. If you already haven't - try removing all unnecessary hardware... then test for problem. Switch your DDR2 RAM in & out to test for defect.
4 - Bad CPU. Not likely but possible. try running the PC underclocked at ~2Ghz(if this mobo lets you). See if the prob goes away. If so, better cooling might be the hot tip

I went throught this and it is really silly. The P5N-T motherboard has a problem with some of the new energy efficient CPUs. The fix was to insert an older CPU and upgrade the bios and then it would recognize the new CPU. If you happen not to have an older 775 CPU laying around (most people do not), it might be easiest to return it and get a different board - or maybe the store can upgrade the bios for you.

How about your screen; is it good?

Your monitor cable, is it damaged?

Does the computer beep, to tell of booting progress?

Is the new MoBo really new? What about the video card?

Try different RAM. Bad RAM will not let a computer boot.
Try booting the MoBo out of the case: lay it out on wooden surface and plug in power supply and monitor, then turn on. Listen for beeps, HDD cranks. Also watch the screen.

Come back after doing these checks so we can isolate the problem.

The beep codes are not universal, but there are a few popular BIOS's and you can figure out what 2 beeps means if you can find your BIOS listed here:

http://www.computerhope.com/beep.htm

The name of your BIOS should appear on the monitor as you're booting.

Was the heatsink screwed into the mobo or was it clipped to the plastic? If it was screwed on the processor is soldered to the mobo and cannot be removed. If its a ZIF socket then more than likely the lever has broken off and the socket is pretty useless now, time for a new mobo.