Computer doesn't start Please Read

[Rzez]

Ok.... Will try to explain everything hear.... To make things easy for you all
My comp is:
Windows Vista x64 service pack 1
Intel Pentium  D 3.2 ghz
8gb of Coursier memory
2 x nvidia 8800 gt in sli
800w psu
asus p5k-deluxe
antec case
.....
 Rite, now the problem...
 When i try to turn the computer on it doesn't do anything..., absolute nout, if i switch off the wall socket and turn it back on the fans turn and lights come on for a split second then nothing again....
 The only way i can get it to go again, is to remove the graphics cards, and disconnect the power supply to them, then reinsert them 1 at a time, making sure the green light on the board glows each, after each 1.

 This happens everytime i turn off the computer, and as of which is really getting on my nerves... Everything works as when i connect it all again, it all works fine and dandy... Far Cry 2 and everything....

 Any ideas?? Will leave comp on so i can check my emails for now lol. Thanks in advance
Mike

[patio]

Did you assemble this machine yourself ? ?

Were MBoard standoffs installed ? ?
Thermal paste used ? ?

What make is that PSU ? ?

[Rzez]

yea i did build it myself... probably the problem
mb standoffs am guessing are the metal points underneath the motherboard that the screws to fix the motherboard into place screw into, So yes is that answer...

thermal paste on the cpu to fan? was brand new so already came with it i believe... as there isa  sticky residue between the fan and the cpu

psu was oryxx titan, did email wear i got ti from and they said i could send it back for them to take a look at it, but surely if the computer does turn on after a lot of reassembling, the psu is fine? (could be wrong)

Any ideas

P.s Thank you for replying

[Rzez]

Ok, looking back over at ur advice, i saw that i was missing 3 standoffs... so took it all apart again, put them in with screws, and changed over my sata cables and dvd cable with the factory ones, and all booted up 1st time, so am going to say thank you for all your help and hope that the standoffs were the problem!!!

Many thanks and happy knew year

p.s just noticed i put it into the wrong thread, shoudla beeen hardware, sorry!!

[patio]

It may be a good idea to re-do the thermal paste so as to protect your investment...Intel stopped pre-applying it awhile ago in their OEM/Retail boxed units...
Thermal Paste Guide

Not familiar with that PSU but there's alot of them on eBay...not that that means anything...
If you can borrow one for overnight testing however you can eliminate it as a suspect...

[killerb255]

It's amazing what problems missing or misplaced standoffs can cause.  They're metal, so they can easily short out something important.  I've been down that road myself a few times.