Youve already done the priliminary testing by booting with only one stick. now you need to get memtest86+ and run it with each stick individully over night. That should help you figure out which stick is the problem.
Well I just tried booting up with my friends ram and it causes the same problems. Is it possible that it's the motherboard that's the problem?
Although rarer, it is possible that the RAM slot itself is broken. Try running the sticks in every combination of the slots possible to test for this.