Pc suddenly turn off

[michaelmk86]

Before three days I upgrade my pc from (q6600+G33+DDR2) to (i7+x58+DDR3) and every thing works grate, no stability issues, very good temps, and grate performance (as expected). After three days of using my pc suddenly turn off. When I try to turn it on, it turns on for less than a second and after it dies.

I checked cables and nothing is loose or anything like that.

I test the power supply to another system and it works.

I replace the graphics card with a 8800GTS and still does the same thing. I try to turn it on with out a graphics card still does the same thing.

I remove the battery to clear CMOS several times and still no help there.

I removed all power and SATA cables connector to HHD and DVD drive and all the fans, didn't work either.

So I end up having the PSU connected only to the cpu+cpu_Heatsink+mobo+ram and still does the same thing.

Any help would be appreciated.


configuration
CPU: i7 920 D0
CPU Cooler: Prolimatech Megahelms
Motherboard: GIGABYTE GA-EX58-UD4P
RAM: OCZ DDR3-1600 6GB
Vega card: NVIDIA Geforce GTX 295
Hard Drive: Samsung SpinPoint T166 HD501LJ 500GB
DVD-R: DVD+/-RW
Power Supplie: Corsair 620W HX Series
Case: THERMALTAKE SPEDO ADVANCE
Operating system: Windows VISTA Home Premium 64bit

 

[kbrm82]

Does it get past POST (power on self test) you should hear a beep, the type of beep (if you get past POST) can be an indication of the problem.

Also when it turn's off does it stay that way or does it continuously reboot?

 

[michaelmk86]

Do not past the POST(no beep).
It turns on for less than a second and after it dies. But some times it turns on for less than a second and after it turns off for two seconds and then agene it turns on for less than a second and dies.

**Edit **
Some thing that I forgot to mention is that from the first day of my upgrade the mobo never post something on the screen (even if I have enable from the bios ‘show starup logo’) on the start up and after boot windows normally with out any issues until now that cannot even turn on.