GA-p35-ds3r rev 2.1 POST issue

It's hard to know -- try installing just one stick of memory. Also, if you can, try the various components in a different system, or components from a different system in yours. I'd start with the video card. You might be able to find a very cheap older/slower video card for very cheap to use for testing purposes in general (I try to keep one on hand for this purpose).

I went through 2 of these MBs with very similar experiences. I let mine run 24/7, so I figure they just wore out. I am very familiar with the 1/4 spin on the CPU fan. So much for ultra durable. I finally gave up and built a new system with an i7.

That would seem to point to bad RAM.

The following is my "standard" "New Build won't POST" reply:

Pull everything except the CPU and HSF. Boot. You should hear a series of long single beeps indicating memory problems.
My GA-EP35-DS3P and eVGA 680i motherboards both do this.

Silence here indicates, in probable order, a bad PSU, motherboard, or CPU - or a bad installation where something is shorting and shutting down the PSU.
Since it worked previously, you can eliminate a bad installation.

To eliminate the possiblility of a bad installation where something is shorting and shutting down the PSU, you will need to pull the motherboard out of the case and reassemble the components on an insulated surface. This is called "breadboarding" - from the 1920's homebrew radio days. I always breadboard a new or recycled build. It lets me test components before I go through the trouble of installing them in a case.

If you get the long beeps, add a stick of RAM. Boot. The beep pattern should change to one long and two or three short beeps.
Both motherboards also do this.
Silence indicates that the RAM is shorting out the PSU. Long single beeps indicates that the BIOS does not recognize the presence of the RAM.

If you get the one long and two or three short beeps, test the rest of the RAM. If good, install the video card and any needed power cables and plug in the monitor. If the video card is good, the system should successfully POST (one short beep, usually) and you will see the boot screen and messages.

Note - an inadequate PSU will cause a failure here or any step later.
Note - you do not need drives or a keyboard to get this far.

If you successfully POST, start plugging in the rest of the components, one at a time.

---------- End standard reply

Your symptoms do not rule out the PSU.

Normal powerup sequence (preboot):
Turn on PC. PSU output voltages rise to rated values (takes a couple hundred millisecs or so). After that happens, the PSU sends a control signal to the motherboard called "PowerOK". The CPU needs that signal to boot.

If you have access to a DMM, you can check the main power supply voltages: the orange wires should read 3.3 volts, red wires: 5 volts, and yellow wires: 12 volts at the main power connector to the motherboard - carefull, carefully  . Output tolerances are +/- 5%. You can have all the output voltages, but if you have some kind of internal PSU failure that kills the PowerOK signal, nothing will happen. The good new is that this is relatively simple to check. Check pin 8 (gray wire) With the PC off, you should read 0 volts. Turn on the PC. The line should rise to about 5 volts (anything over about 3.5 volts is OK) in less than one second.

Well thanks very much for everyone giving me some advice.
Thanks especially to jsc! =D
Basically followed you instructions of POST diagnosis

So I stripped down the machine to the MB, CPU and HSF. And started testing.

CPU + HSF only
3 beeps followed by 7.5 beeps, then powers down and cycles this pattern
HSF spinning like normal

ADDED RAM
First 1 stick and then both sticks
Both additions gave a sort of morse code beep-be-be. Definitely not a long beep. It was a shot beep, followed by two more speed beeps that seemed overlapping. (sorry its hard to describe!)
HSF still spinning normally

ADDED Graphics Card
No beeps, fans started doing the 1/4 spin. Also power is not cycling. It turns on and does the 1/4 fan spin.... Then nothing!

So basically I still have no idea whats going on here. From jsc's info I would guess it is a PSU issue?!
Any further advice would be hugely appreciated!


NB. I am unfortunately unable to test my equipment, like PSU and Graphics Card as this is basically my only setup. I have some old gear, but none of it is compatible with this newer PC (like AGP graphics cars, SD RAM etc). No DMM or anything like that either. =(

I have found a PSU tester to be an invaluable tool. Only $20 or so at the nearest Fry's. This tool has saved me many a long nights in troubleshooting and is well worth the investment.

PSU's do fail! In 15 years of doing my own builds, I have had at least 3 PSU's fail.

I would bet PSU is your issue.

Yeah, and if you're not lucky enough to have a 'local' Fry's (I'm envious), try these:
http://www.newegg.com/Product/ProductList.aspx?Submit=E...

UPDATE:

Turns out it was my graphics card.
Was an easy diagnosis when I had en extra PSU, graphics card and ram at the shop to test with.

Graphics card has been sent to the manufactures, but it was about one week over the one year guarantee! Typical.....

Thanks for everyones help

You know why a card with a two year warranty costs more than a card with a one year warranty? 'Cause it costs more to supply a timer that causes it to fail at two years and a day, than it does one that fails at one year and a day...