I don't normally do this, but help please!!

I'm having a few problems with my PC at the moment
I'll try and keep it as brief as possible...
Mobo seemed to have failed, so I RMA'd it, it was tested as faulty and I was refunded. I bought giga GA M57SLI-S4, had pretty much the same problems as before.. (Occasional display, hang on BIOS and in BIOS, although I don't get a display at all now ) I've tried with components from old Skt 754 system and haven't achieved anything. I've tried all 5 of my HD's to no avail, my 8800GTX & 6800GS, half the RAM, my old 360w PSU (obviously not with the GTX )
Basically just need a fresh set of eyes to go over the problems and see if I'm missing something simple!
Basically, everything turns on with the switch, fans, HD, optical etc. but I get no display. I tried old PSU and got nothing, new PSU in old PC, nothing so I can't rule the PSU out.
I've added the thread in mobo section where I discussed some of my problems as well. Thanks for any forthcoming help!
Much appreciated!

id say get another new psu....the psu could be messing things up...

Thanks very much for the above, much appreciated!
I realised I confused a couple of points in my post (I'll admit thats because I was really pissed off! ) I have tried my old and new PSU in both machines and had no display from either. I guess there is a possibility that the PSU is screwed and when I tested it in my old machine (which was fine when I left it 2 months ago) it fried it the moment I hit the power button. Interestingly, I've had no signs of damage to any of the compnents. I'm tempted to buy a new PSU (I have my eye on the CoolerMaster 850W) and RMA the mobo & 750W XClio PSU. See from there...
Good idea or not?

I haven’t overclocked at all though!
Basically, it goes like this –
Machine 1: skt 754 3700+, no RAM, 6800GS 256mb
Machine 2: skt AM2 6000+, 4Gb RAM (although I’ve been using 2), 8800GTX/the above 6800.
PSU 1: Asus 360W
PSU 2: XClio 750W
I have tried both PSUs in both machines and have had no displays from either.
I’m going to buy the CoolerMaster 850W this evening and RMA the AM2 mobo & 750W XClio and hope that I won’t have any problems from there!
Unless there are any other suggestions from people on things to check?
Thanks

Yeah I do wonder if thats the case!
I've just ordered a new one (the CoolerMaster 850) for £108 ($220 ish) so I'm happy
Should be here thurs so I'll see whats been fried
I hope it stopped at the board as it had some frighteningly expensive components connected to it!
A brand new RAID controller and 2 150 gb Raptor's + a 36gb raptor
Anyhoo I'm going to RMA the board and PSU and start as a clean sheet.
I hope....

What is your exact PSU? It is probably the PSU, if every thing else passes/works on another PC or passes benchmarks.

You could try and open up the PSU and see if you have bad capacitors. This is the usual cause of PSU failure.

http://en.wikipedia.org/wiki/Capacitor_plague

Look at the pics, and see if the capacitors are like that. If so you need a new PSU.

OOps I didn't see the above post that it is a tier 5 PSU which is garbage, this explains a lot. You buy a tier 5 PSU and your asking for trouble! One of the most important part of a computer is the power supply. Your so lucky it didn't fry your hole computer. The quality of the PSU you buy will effect how long your components will last, in this case it was a few seconds. I see why now you have had so many dead mobo's.

coolermaster isnt that bad...

I have two TOPOWER 520P units in my best two rigs - been running for three years ...

On examining the insides I find top quality components ...

Sorry to go off-topic.

The rest of mine are Antec ...

No I was really being realistic because I have known others that have bought tier 5 PSU's and they fried their hole system and taking their surge protector with it. I was kidding about living with your parents because the poster before me said, "systemlord is harshhhhh why don't you kill his... So I was being funny about it. Cheers and have a happy holiday.