Confusing possible RAM issue

Hi guys, I'm building a new PC with some of my friends and we're having an issue. We had everything working, turned it on, and saw a message on the screen to insert bootable media. Before doing that we decided to close the case and stand it upright.

After turning it back on we got a white screen and a single beep from POST. We have an AMI BIOS, so that means Memory Timer Error according to the manual. I reset the BIOS with a jumper and now it gives me a white screen and two beeps, which means RAM Parity Error. The only thing that changed between it working and not working was being stood upright (it's back on its side and open again now).

If anybody knows how to fix our problem that would be awesome. We have a Biostar A770E3 motherboard, with two 2GB sticks of DDR3 ram (I've tried them individually, same problem).

Thanks in advance