This type of problem is often the result of overclocking the CPU or memory intentionally or not. Try setting the BIOS to its default settings. You can also try resetting the CMOS memory, another thing to try is to check for BIOS updates as your processor may not be fully supported with your current version. Also try a memory test program as the memory might need a higher voltage or reduced timings etc.
This is good advice. Are you OCing anything?