Hi everybody, I have this problem: the computer only TURNS on and BOOTS with a 1 GB Apacer 800 MHz RAM.
Adding more RAM results in pc suddenly turning off while booting  (which sometimes happens also with that single RAM only) or even not turning on at all.
I have another RAM which is exactly the same as the one I'm using and adding it I encounter this problem.
I also tried with another two RAMs (2 GB VDATA) and the computer doesn't turn on, the  power button intermittently flashes. Switching between every slot didn't change anything.
My OS is Windows 7 with American Megatrends BIOS. I don't know what to do, changing motherboard? Changing power SUPPLY?
In my opinion the problem isn't the RAM.Was this system originally running ok with all of these RAM sticks installed or did this just happen after a memory upgrade?

The computer ran ok with the two Apacer sticks and another one but a day the computer started to suddenly shut down during the use.
I put off a stick and everything was working normally again until 2 or 3 weeks later, when the problem appeared again and became every day worse than before.
I put off another stick (I had the two Apacer ones on) and the problem SEEMED to be solved but after some days here it was again, even with only one stick.
Now I'm using only that stick and have to try to turn on the computer over 10 times to get it booted and working. It doesn't turn on at all if I add another stick.What MBoard is this ? ?The motherboard model is MCP78PVM-PM.A Chinese made MBoard that was used in some Packard Bell and other desktop PC's...almost impossible to find any specs on it.
What type and speed is this RAM ? ?1 GB Apacer 800 MHz is the one I'm using right now.I somehow doubt a board that old would accomodate any 1G RAM sticks. Quote from: patio on October 19, 2013, 09:36:24 AM

I somehow doubt a board that old would accomodate any 1G RAM sticks.

The motherboard model is MCP78PVM-PM.

mcp78pvm-pm specs

4 * 240-pin DDR2 DIMM slots – Dual Channel DDR2 800/677 MHz non-ECC, un-buffered memory (Max 8GB)