Took all day to download Mass Effect through Steam, finally get to play it and about 20 mins in (after messing with resolution etc.) the screen goes black and the PC looks like it has reset.

Monitor light goes to amber (standby) and the DVD drive light is flashing so I press the eject button thinking it's trying to boot from a DVD. Tray comes halfway out (no DVD in there) and then all the power goes off.

Press the power button on the front of the PC and it goes to startup for 2-3 secs, no beeps, and the shuts down and then starts up - over and over. Have to switch off at the PSU switch to stop it.

I opened the case up and change out the 3D card - same thing. Remove 1 stick of RAM - same thing. It was midnight at this point so I left it.

I am thinking it may be a PSU issue. I initially thought it was the 3D card as I had problems previously, but there were no graphical anomalies before it happened and a change of graphics card resulted in the same outcome.

I am going to try a spare PSU tonight and then if still the same try a bare boot with just the mobo, CPU, RAM and 3D card connected. Thing is it's a 650W Corsair PSU and only a year old and connected to 1 hard drive, 1 DVD combi drive, 2 sticks of 1Gb RAM, GeForce 9800GTX+ and has been fine for over a year. That PSU should be fine with that setup, right?

Never had a PSU go on me, is it likely to be that from what I have described? Any ideas?

Cheers

Wattage is plenty, brand name PSU - either that or the Mobo bought it. How old is the Motherboard?

It's about 1 1/2 years old I think. It's a Gigabyte 965P-DS3. The 3D card fan starts spinning straight away and then as the CPU one is just making a quarter turn it switches off.

Just read on the Corsair helpdesk to do the paperclip test. Make a U shape from a paperclip and stick one end into the green wire part of the 24 pin ATX connector and another into the black wire part whilst it's plaugged in and live! If the fan doesn't spin it's bad...

If I blow up it's good I guess lol.

Make sure the CPU fan is seated over the CPU correctly. If the vibration over time has worked the fan loose (away slightly from the MB) the PC will sometimes do what you describe.

It happened to me not so long ago - something to look at anyway.

I have just checked and the PSU is 1 year old on the 5 November!! I better get it tested.

The RAM, mobo and CPU were all bought in March 2007.

Buccaneer has a good point, it could be self-protection shutdown from an overheating CPU. The Mobo should be well within it's lifespan.

Just been home on my lunchbreak and tried to do that PSU test and there were about 6 black wires!! I picked the one furthest from the green but nothing happened. Anyone know which one I should use?

My other PSU has a smaller main power connector, might be a 22 pin? This won't go into the connector on my mobo...bugger!

I looked at the CPU fan and it seemed to be seated ok or are you saying I should remove and re-seat it? Hope not as it's an Intel one and is a real pain to get on.

Can you get into the BIOS menu? Is the date/time correct? If not, check the battery to make sure it's seated well, could be dead, but it should last a lot longer than 2-3 years.

I am going to have to take to a PC repair shop as I cannot test the other parts as I don't have them. It's £10 for just testing the PSU (which I was just going to take) or £30 for the whole PC... I am sure I had anther PSU with this mobo though as I had to upgrade to the Corsair because I bought the 9800GTX+, will have to have a search first. Hope it is the PSU as it will be in the manufacturers warranty still.

It could be the PSU, THE Reset/Power Switches or Pins, The CPU Temps, or something loose on the mainboard causing a power flux.

1. Disconnect the PSU Cables.. Check them for loose wires
2. Remove Heatsink fana nd re-seat.
3. Check Power/Standby and Reset switch pins on the mainboard
4. Check for loose hardware or connectors.

Will have a look tonight after work and see how I get on...will let you know.

Thanks all.

This same thing happened to me once, but I was playing Silent Hunter 3.
It turned out to be the CPU that died on me, which is rare specially on a non-overclocked rig.

well I just sent it back to the retailer and got a replacement.

have you changed any BIOS settings? the only time I've had something similar is when I've messed with the BIOS for OC'ing and set wrong parameters. You might reset it anyways just to rule it out (either take the battery out or short the pins (should be in the manual).

If it's not that then I'm guessing it's a heat/power issue like the others suggested

I never OC and I haven't touched the BIOS in ages. Tried another PSU and the same thing happened so it's not that. Took the HS/fan off and the paste that was on has dried up and is pretty non-existant so it may be that, either overheating or as Spede mentioned it's damaged the CPU.

It's 2 years old so I doubt they would replace mine. I am thinking of getting a whole new rig actually as I couldn't get the HS/fan back on and thought I had cracked the mobo with trying to push it back on - I hate the Intel HS/fan units! Just need to see if I can get the funds!

The date/time was correct? Not the OS, in the BIOS screen.
When that battery goes all kinds of odd things can happen since the system clock isn't keeping time.

It starts for 2-3 seconds and restarts itself...doesn't get anywhere near the BIOS screen!

Maybe time to pull as many cards, drives, and memory modules as possible and see if you get a boot with a minimal build? Even with no HDD or OS getting to the BIOS would be a hint.

PS... One of my mobo failures had undeniable traits, such as the PS2 sockets not working anymore. Another was very subtle, the mobo would return errors with the memory module in the second slot. Any module would error there after hours of Memtest. The contact joints between the socket and board had failed, somehow.

I did a minimal build test, just mobo, graphics card, RAM and CPU connected and still the same. I am going to use as an excuse to buy another and try and fix afterwards and use as a backup machine so still need to work out what it is. I have always built my own PCs and always sorted out the problems but this has me stumped....

Yeah, that's bad. LOL
The yank everything plan sounds right to me too, can you pull that graphics card too? Do you have onboard video?
I wouldn't think it's a heat issue that fast, if it does it cold, but does sound like a hardware issue and something is just malfunctioning.
How many sticks of memory do you have? Can you scale back to 1 stick, test, then yank it and put in another stick etc?

If the "yank everything" trick can't get you to the BIOS or to a "no operating system found" message, I would suspect the motherboard has gone south for the winter.

I did yank everything and still the same so I think it's 'left the building' but got some money sorted for new system and get one in the next few weeks. Thanks for the input guys

Ah, that new pc smell! Good time to move to Win7 if you haven't already. I think that will be my excuse for a new Ion based netbook early next year.

Yes, I'm getting Windows 7 . The DVD drive had been playing up too so that's my excuse, I mean reason for a new one lol. What is the difference between the 32 and 64 bit versions?

32bit can only use ~3GB of RAM; 64bit can use much, much more. Also note that the software you run needs to be 64bit also to utilize the most RAM; but 32bit apps will still work (just can't use as much RAM). As of right now there's really no reason not to go 64bit since (hopefully) more and more companies will start writing software for 64bit

I went 32 bit, since one of my FS9 addons is a 16 bit external app, which won't run under 64 bit OS. And I can choose 64 bit later if it's needed.

No real loss, since I have no plans on upgrading my 2GB of memory anytime soon.

if running bare bones dont do it, its the CPU, BIOS, VRM or something that regulates the power on the board..