Just built my first computer, won't start D:

[Robothax]

Hey guys, I just finished constructing my first computer, and when I plug it in and press the on button, it doesn't start. I do see the flash of the power supply's LED, but only for a brief second, and then nothing. I understand that it could be that I may have assembled it wrong, but I did check and recheck all the wire connections, the pins, etc. Is it an incompatibility problem? Is it that one of my parts defective? Help please :P

Motherboard: MSI P6N SLI Platinum LGA 775 NVIDIA nForce 650i SLI ATX Intel Motherboard
http://www.newegg.com/Product/Product.asp?Item=N82E16813130081

Memory: CORSAIR XMS2 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) x2 (4GB total)
http://www.newegg.com/Product/Product.asp?Item=N82E16820145590

CPU: Intel Core 2 Quad Q6600 Kentsfield 2.4GHz 2 x 4MB L2 Cache LGA 775 Processor
http://www.newegg.com/Product/Product.asp?Item=N82E16819115017

GPU: EVGA 640-P2-N821-AR GeForce 8800GTS 640MB 320-bit GDDR3 PCI Express x16
http://www.newegg.com/Product/Product.asp?Item=N82E16814130071

HD: Western Digital Caviar SE16 WD3200AAKS 320GB 7200 RPM 16MB Cache SATA 3.0Gb/s
http://www.newegg.com/Product/Product.asp?Item=N82E16822136074

PCI Wireless Card: MSI PC60G IEEE 802.11b/g 32bit PCI2.2 Turbo G Wireless Adapter up to 54Mbps Data Rates 64/128-bit WEP, WPA, WPA2, TKIP,AES,802.1x
http://www.newegg.com/Product/Product.asp?Item=N82E16833158017

DVD Drive: SAMSUNG Black 18X DVD+R 8X DVD+RW 8X DVD+R DL 18X DVD-R 6X DVD-RW 12X DVD-RAM 16X DVD-ROM 48X CD-R 32X CD-RW 48X CD-ROM 2MB Cache SATA DVD Burner With LightScribe Technology
http://www.newegg.com/Product/Product.asp?Item=N82E16827151141

PSU: COOLER MASTER RS-550-ACLY ATX12V / EPS12V 550W Power Supply 115/230 V UL, cUL, TUV, NEMKO, BSMI
http://www.newegg.com/Product/Product.asp?Item=N82E16817171009

What I thought of was it could be that the Power Supply is either defective or incompatible with the mobo, or that perhaps the RAM was incompatible with the mobo and shorted it out.

Little update: I did take the case cover off this time when I tried turning it on. With both the power strip on and the Power Supply switch on, but the computer itself off, a little orange light on the motherboard is lit that says Stand by Power. I would assume this means that power can run successfully from the outlet to the motherboard? However, on actually pressing the power button the blue LED of the Power Supply flashes and all the fans (Power supply fan, Case fan, CPU fan, and Heatsink fan) spin briefly, powered for about the same time as the LED, and then nothing. The orange light on motherboard, however, does stay on for the duration, and remains on as long as I have the power supply and power strip on.

Night guys, thanks for your assistance. I'll check back in the morning.

[shadowpr]

http://forum.pcmech.com/showthread.php?t=132409

and you never listed what your psu was.

[Robothax]

Ooh, whoops :P

PSU: COOLER MASTER RS-550-ACLY ATX12V / EPS12V 550W Power Supply 115/230 V UL, cUL, TUV, NEMKO, BSMI
http://www.newegg.com/Product/Product.asp?Item=N82E16817171009

Trying out that procedure now.

[shadowpr]

post the reults of that when you get a chance so we know if you still have problems

[Robothax]

I tried out the procedure thing and I'm pretty sure I've found the problem. There seems to be no problem with the PSU, CPU, etc, just the RAM. I tried out each individual stick of ram (I ordered 2 packages of 2 1gb sticks) and none of them allowed the computer to boot. However, then I tried NO ram, and on pressing the power button, everything came on, and stayed on. All the LEDs came on, all the fans were spinning, and a green light on the motherboard that said Main Pwr turned on. However, due to that there was no ram inserted, I got no video, etc, so I couldn't really do anything.

This leads me to believe that either ALL my RAM is defective, or incompatible. Any reasons as to why this would happen? Thanks guys. :P

[shadowpr]

are you sure when you tried each stick indivdually, that it was in all the way?

odds of getting 4 bad sticks has got to be incredible.

[Robothax]

Ok, I had my friend come over and we went through it, we reinstalled everything, took it all out of the case, etc. Everything was connected properly. Apparently I had the RAM was not fully secure when I'd put it in earlier, but it was working now. With everything connected _outside_ the case and on a non-conductive cardboard box, the video card connected to a monitor, we turned it on. No video. I called up evga, (video card manufacturer) and spoke to them briefly. They told me to only connect the bare minimum to get a video, (IE PSU, GPU, Monitor, CPU, Motherboard, and 1 stick of RAM). Again, doing this, outside the case, I still get no video. Is it a motherboard problem (apparently I had it in the case wrong, as it was touching the case when I had originally installed it) or is it a video card problem? I checked the monitor on a different computer so I know that it works. Is there a way to tell?

[flanzig1]

Just to review your power connections, the motherboard has both the main 24 pin AND the 8 pin CPU power conector plugged in? (the 8 pin plug has a cover over 4 of the pins that needs to be removed if the PSU has such a plug). And the 6 pin PCI-E plug from the PSU plugged into the video card.

[Robothax]

All power lines are connected. I checked, unplugged them and replugged them in, and tried again. Same thing, no video. Should I try the video card in another computer?

[waxpants1]

a couple days ago i had the SAME EXACT problem the led's would come one but nothing else. all you need is a new power supply.