Run a memtest86 to test your ram. Download one of the versions here: http://www.memtest.org/#downiso
Burn to a disc and boot to the disc. They also have a bootable flash drive version (backup your flash drive because it requires a format).
If you have errors let me know and also let me know how many sticks of ram you have and their size also what slot each stick is in. I can likely tell you which stick is bad if you supply all of the information (if a stick is bad).
Do you have onboard video or are you using an add in video card? If you have an add in card and onboard try using just the onboard graphics. Try removing all non essential hardware such as wireless cards, sound cards etc. Just power supply, ram, cpu, cpu cooler, hard drive, onboard video, monitor, mouse, and keyboard.