Look at the User's Manual regarding resetting your CMOS settings. This usually involves taking a screwdriver and shorting two pins on the motherboard for a few seconds. Your can then restart your computer.
I suspect that the problem is in your BIOS settings. I am not familiar with that motherboard so I cannot give you specific advice. Is there a BIOS option that let's you automatically load optimized settings?
Check the BIOS settings for memory (Voltage and Timings). What memory settings are in your BIOS? Have you made any BIOS changes?
Try to run Memtest86+ Version 4.0 to check to make sure your memory modules are OK.