RAM or Mobo problem?

Hi there,

I have been experiencing some problems lately and I'm pretty sure it's either the RAM or Motherboard that is causing it. This is the RAM and Mobo which I'm using:

http://www.newegg.com/Product/Prod [...] 6820231193

http://www.motherboardpro.com/EVGA [...] p-543.html

So, here's the situation:

When both RAM sticks are inserted into the slots (regardless of any configuration...dual channel or not), my computer experiences a "boot problem". The lights and fans turn on but the screen stays blank. I have to "reboot" my computer in order for the display to turn on. Also, it "hangs" when I run MEMTEST86 using first boot device from CD and usually never passes more than 5 cycles (because it "freezes" halfway through). However, there are no errors at all which is kinda weird. My computer also "hangs" frequently when I play any video games, watching movies or even surfing the net.

But when either 1 RAM stick is inserted (i've tested both of them separately) into whichever slot, NONE of the problems above happen at all....everything turns on and works perfectly fine.

I sincerely appreciate your kind attention to help me out with this problem. Thank you very much!