15 R1, issues

I have an alienware 15 r1 that I bought a used board for. The board worked for a few days and then gave the 7 beeps for cpu. It sat for 3-4 months before I messed with again, and it tried to boot but I don't currently have a hard drive in it. I ran diagnostics and everything tested good. Then it went back to bootlooping like it used to, so I unplugged the battery, removed one stick of ram and it was able to go into bios/boot menu. I put the second stick back in and it was able to do the same.