BleepingComputer.com: No Display-Fans and lights turn on

My original problem was my computer randomly shutting down without any error messages or anything like that, as well as not being able to turn it back on until after a while, seems like the longer I leave it turned off, the more time I get to leave it turned on before automatically turning off. Anyways so I decided to open up my computer and take out the heatsink and everything else out, and clean the dust off. After fully dusting off the computer I plugged everything back in and now the fans, and lights turn on, and the power supply fan slowly spins before finally spinning after a while. I get no display or any usb mouse light. I tried taking out the CMOS battery and then putting it back in, Also I get no beep when I take out the ram. I tried taking out the video card and plugging VGA unto motherboard. Also the hardrive, it spins so dont think its a hard drive issue.

When I took out the CPU it broke the thermal paste off, so I was wondering if that has to do with anything, if it doesn't detect the heat sink as there's no thermal paste?
Also I am thinking if it might be the power supply and me needing more then 500 watts.

My Computer Specs:
Assus M3N78-VM
OCZ StealthXStream 500 watts P/S
OCZ 2x2gb DDR2 Ram
AMD Phenom x4 9600
Evga gtx 460 768 mb
Lg DVD Drive
Western Digital 1tb Black Edition
NZXT Guardian 921 case

Please Help!

I don't really have any spare parts to swap.
Thanks.

This post has been edited by ak21: 15 February 2011 - 11:22 PM

No thermal paste would be a very bad thing = no thermal coupling to the heatsink, as you guessed.

Symptoms could also indicate a failing/underpowered power supply.

The graphics card usually is the major power draw (details for your card here say minumum 450 watts). Do you have onboard graphics that you can revert back to to try?

Edit: Had missed this...

ak21, on 15 February 2011 - 11:15 PM, said:

I bought thermal paste and applied it to the cpu, so that gets rid of the thermal paste, also checked my work, and my brother checked it too, everything seems to be plugged in properly. I think i might as well just rma some parts back, seems like the simplest way of fixing it, as I don't have any spare parts to know exactly what part is the problem. Is it possible to destroy the power supply if its trying to provide more power then it can, since my computer worked when I got the video card, but like I mentioned like 2 or so days after the graphic card is installed, the computer kept turning off. Now it doesn't even show any display or anything.

I heard it might also burn the motherboard if the power supply can't supply enough power, is this actually true? Asking since it does make sense if its the motherboard as all fans turn on, that's plugged into the power supply but all usb,vga etc.. plugged unto motherboard don't work and I hear no beep when I take the ram out.

Sorry for the very late reply, and double posts,but I rma'd back the motherboard and cpu and got them both back, for the cpu, it passed all tests for the motherboard they just replaced it, but I believe it passed the tests, and I am still having the same problem. I believe its the power supply. The reason why I think this is because of process of elimination and I also did the paperclip test, and it didn't spin, nothing did. Plus, the psu fan doesn't spin even when connected unto the computer. I also did a psu wattage calculator on different sites, and I would say it averaged out to something like 550 watts. I am thinking of just buying a new one, even if it ends up not being the psu, I still need to upgrade, right?

Please give me your opinions, but if I do buy one, I was thinking of these two, and any others you guys may suggest in my price range (under $100).

Current 2 I am thinking of:
Antec Truepower New 650W Modular Power Supply $70: NCIX.com - Buy Antec Truepower New 650W Modular Power Supply ATX12V V2.3 Active PFC 80 Plus SLI Ready 120MM PWM Fan - Antec - TP-650 - in Canada

OCZ ModXStream Pro 600W $50 ($30 M&R): NCIX.com - Buy OCZ ModXStream Pro 600W ATX 20/24PIN SLI Ready Modular Cables 135mm Fan Active PFC Power Supply - OCZ Technology - OCZ600MXSP - in Canada

This post has been edited by ak21: 08 April 2011 - 11:16 PM