Home Built media PC problem

Hopefully someone here can help me otherwise ill have to take it into work to get our IT guys to check it out.
Here is what i have:
Gigabyte GA-EG43M-S2H motherboard with HDMI out
Intel Core 2 Duo 2.5?Ghz processor
2 x 2GB DDR2-800 RAM
Corsair 550W power supply
1 x 500GB Harddrive
1 x 80GB hardrive
All packed into a nice Silverstone LC16M case

Now the issue im having is that it randomly decides to shut itself down, not a shutdown as such but a cutout. Then subsequently tries to power back up but cuts itself out again and continues doing this until i switch off the power supply. I can leave it for awhile and it may startup again for awhile but then will randomly cutout again, or it just goes through its attempt to startup.
Looking inside i can see the diodes by the RAM light up as its about to start and the CPU fan starts up, then i hear a small beep sound and it all cuts out.

Any ideas?
I have pulled it apart and put it back together a couple of times now and it usually works fine for about 12 hours then starts going through this process again.

Its getting extremely frustrating.
Just for the record i am running windows 7 RC on it but i dont think that has anything to do with it.

Help appreciated.

could be a loose connection or over heating. Make sure the cpu heat sink is attached properly.

Next try unplugging everything other than MB and CPU, go from there adding things back in and see if you can narrow it down.

Yeah I'd suspect an overheating problem there too.

Ok so the CPU fan it attached properly, even used thermal paste as advised.
Is there anyway to check temperature for the processor?

often in the bios if you can get that far.

next perhaps swap out the power supply

Ok so i have unplugged everything except the harddrives, motherboard and power switch control and its still doing it. The harddrives are hot but the air around the cpu is not and i have had the cover off the entire time.

Bugger i hoped that wasnt going to be the next option. Might have to take it into work now.

when i said unplug everything from the power but the mb and cpu what i really meant was everything but the mb and cpu.

hard drives and even the ram if you feel up to it.

Ok gone back to scratch and i think i may have found it.
Worked fine with just cpu, then 1 harddrive, then 2 hardrives then when i put in the RAM it strted erroring out. Tried both sticks in slot 1 and they both did the same thing. Have got it in slot 2 now and its running fine. Will try that for awhile and then try 2nd stick in slot 4.
The odd thing about this is that the manual says to use slot 1 and 3 first.

wait..there it goes again............so its gotta be faulty RAM then?

http://www.memtest.org/

Or faulty memory controller on the MB, though its a rare issue.

check you have the right ram for the mother board too.

Just how do you start you computer with no RAM?

I can almost guarantee you its a CPU problem.

Yeah I'm with reaction on this one.
I built my flatmates system for him a few weeks back. The only bit he did he did himself was sticking the cpu and fan on. He did'nt know what he was doing and without me checking it stuck the fan on.

Switched on the system and it would just cut out randomly after POST. Sometimes it would get to loading windows screen, other times, five secounds after boot. Initially I thought it was ram or possibly his graphics card drawing too much power but after some checking, tracked it back to the CPU.

Are you 100% sure you've installed the CPU right, with a thin layer of thermal paste covering the metal heat spreader on the top of the CPU?

As i said i would suspect an overheating issue with the cpu. But you can turn a computer on with no ram and wait for it to hit the thermal cut out. You can also check the temp of the cpu in the bios which he should have done.

If it cuts out without ram in it then you know its the cpu, psu or motherboard.

Did you use conductive or non conductive paste? Make sure you didnt put too much on it and it squirted out the sides.

where you even meant to put paste on?

some CPUs don't require thermal paste, because they have a integrated thermal interface..

Ok so took it into work and guess what.....now it wont cut out. Got fd up and left it there over the weekend. Will troubleshoot more on monday.

As for the thermal paste not sure what it was but i got it off our IT team and had 2 guys there who have built many PC's before as we put the CPU in and fan on.

Will try and get an update on Monday as we tried to flash the BIOS but wouldnt boot from disc.

Ok so reminder never to trust the guys at work......

What we found was the CPU fan wasnt put on properly so it wasnt making contact with the CPU.
Refitted and went fine.

Cut out another couple of times randomly but havent had an issue....till now.

Why does Media Centre chew the cr*p out of my CPU when watching TV?
It keeps cutting out as it cant handle the strain. When i minimise the MC screen to watch the processor its going nuts non stop until it just kinda gives up and loses audio then picture.
Surely it shouldnt be putting that much strain on it.

so you didnt even check it till now?

Its possible its fucked, even 100%cpu for 20 minutes shouldnt cause overheating unless you have overclocked or the cooling isnt working.

Its possible its the onboard HDMI causing high CPU, try using normal vga out or playing into a monitor.

I assume your watching normal HD videos or something similar. I have a Dual core 3ghz/ 4gigs ram and a 8800GT 512Mb ram and even it struggles with raw HD video taken on a Panasonic HD video recorder. Though im not sure media player even plays those files yet.

Yeah i had one of the guys at work check the CPU and fan and he said it was fine at the time which is why i didnt unmount and remount it.

But is it likely that is the issue in this circumstance? Its fine with everything else. Just media centre runs it extreme
Chip is a Core2 Duo E7200 2.53Ghz

Checking the reliability function in Windows 7 it shows that i have been having multiple video errors and it cant find a solution at this time.
Will just have to keep trying updates i guess

Well the TV was Freeview via a USB tuner, but have just been watching a standard downloaded movie (not high def) and it just died on me about 30 min in.
Have now unplugged the HDMI and am running VGA and SPDIF....Will see how that goes

and try a different program like vlc (videolan.org) that you can change the graphics mode on.

Ok so this is now getting a bit weird.
Imagine this.
I have an LCD TV, Amp, DVD recorder, PS3, Sky and my computer all running from one surge protector.
I flick on the heater at the other side of the lounge and my computer flicks off again and continues trying to restart.
With the heater off it seems to work fine eg has been running all day with no issues.
Does that make sense?
I know it will be to do with a cut out but why is it that its just the computer failing not anything else.....and is it likely then that when the computer is working hard it forces this situation itself hence the cut out?

Anyone?

The heater might be faulty and or your power supply on the computer might be bung.

Is it a passive surge protector or a power conditioner?

Heater is about 1 year old, electronic and really good nick.
Surge Guard is a Belkin 8 port surge guard, so not a power conditioner.

I guess its possible the power supply in the computer is temperamental, that would explain if the power fluctuated that it couldnt handle and kept cutting out?

old heaters and multi boards fail all the time, new ones occasionally. a few devices on a powerline which are leaking or causing problems and you can get some really ugly spikes which would cause the spike protector to cut out just long enough to piss the computer off.

Also, check all your connections on the computer to make sure the hard drives etc are plugged in properly there might be just enough connection to be ok most of the time but not when theres an issue.

Buy a power conditioner if youre really worried, it will probably cost less than all the time youre spending on this.

I have a 600VA one of these and used to hear it clicking in all the time. http://www.ascent.co.nz/productspecification.aspx?ItemID=9346796