[phr33zr byt3]

I built a new computer about a month ago and it was working fine until about a week or so ago. The specs are as follows: Biostar TA890-GXB HD motherboard,AMD Phenom II x6 2.8ghz 1055T processor,2x2gb of a-data 1600mhz gaming ram, and a ocz stealth xstream 500watt power supply. It started freezing while i was typing or working on something,everything would freeze keyboard, mouse,operating system. That would normally be after 30 minutes or more,but the time gradually became less and less until now where it does it every minute or the computer doesn't boot at all. When it does boot it comes up with a message and says "DQS training failed on previous boot,reverted to slower DRAM speed". I have tried taking each ram module out and running with the other in,but with no luck. I have also reset the bios to default and changed memory settings,which didnt work either. All the cpu and case fans are working and the cpu is not overheating. I have never overclocked the system. The system freezes wether it boots long enough to go into the operating system or wether I am in the bios. Does anyone know what might cause this or have had similar problems?