Either the RAM on your system is faulty or the slot that the RAM is installed in is faulty. To check your RAM, use the Windows Memory Diagnostics utility. Open the utility by pressing the '''''Win + R''''' key combination and enter '''mdsched''' in the Run box. Then follow the prompts provided by the utility.
If Windows Memory Diagnostics does not see a problem with your RAM, then the problem may be with the RAM slot on your motherboard instead, and your motherboard may need to be replaced.