Is this a Powersupply problem?

Perhaps , I just wonder if you have overcloak the system it does that , see if the memory is running at the factory mhz example if you have ddr3 1066Mhz don't forced to 1333 mhz, make sure the system Hper trasport Bus if capable to change and is not below of what is capable I think is from 2000 up to 5200 Mts or better yet if you have made changes in the bios set back to defaults and try .oh another note have you ever check for registry errors ... errors there can also cause that too.