Serious problem

[Guest]

I have a gigabyte ga-ma790gp-ds4h motherboard,a phenom II x4 (3.40ghz),4gbs ocz ram(2 sticks),2gbs of ballistix ram(2 sticks),a 500watt psu.It was working fine until last night.I went to turn it on,it started to boot and the screen went black.after 20 minutes i had tried to restart it an it didn't post,beep and i had a black screen.I had took out the battery,changed the psu(750watt,new),changed the ram and still nothing.i'm using the onboard video(ati hd 3300).2 weeks ago i had a hardware failure(bsod)which i thought was the ram because after changing it all the computer ran fine again.i took a chance 1 week ago,put the old ram back in and it again ran fine until last night.i did let the computer sit unplugged for 6 hours then it started once,after that i had no post again,no beeps or anything.i have never over clocked the system.what could my problem be?the mobo or the processor.

 

[jaquith]

I have a gigabyte ga-ma790gp-ds4h motherboard,a phenom II x4 (3.40ghz),4gbs ocz ram(2 sticks),2gbs of ballistix ram(2 sticks),...

Remove ALL DDR, next place "brand 1" in DDR2_1 & DDR2_2 ; leaving "brand 2" out. Does the BIOS Post?
Failure, swap-out and install only "brand 2" in DDR2_1 & DDR2_2 ; leaving "brand 1" out. Does the BIOS Post?
Failure, try both ways - "brand 1" in DDR2_1 only, and "brand 2" in DDR2_1 only.

Please post either the Part-Number and/or Link for each of your DDR memory. {Verification Certified / Tested}

reference:
MOBO - http://usa.asus.com/product.aspx?P_ID=gFBKfNyhppW9tDbB
4 x 1.8V DDR2 DIMM sockets supporting up to 16 GB of system memory (Note 1)
Support for DDR2 1066 (Note 2)/800/667 MHz memory modules
(Note 1) Due to Windows Vista/XP 32-bit operating system limitation, when more than 4 GB of physical memory is installed, the actual memory size displayed will be less than 4 GB.
(Note 2) Whether 1066 MHz memory speed is supported depends on the CPU being used.

 

[socratesx]

First of all check all your DDR dimms one by one to all RAM slots. That way you will find if the RAM is causing you problems. If you can find a spare video card install it and check if the system posts. If nothing works then maybe it is a problem with your mobo.