Probably one or more of your installed RAM modules are faulty. Test them one at a time (by having only one module installed at a time) using Memtest86 on a bootable CD or USB pen drive. The CD images for MemTest86 V6.3.0 Free Edition are here: http://www.memtest86.com/download.htm
Note: The CD or USB image will automatically make a CD or USB pen drive bootable, you don't have to manually make them bootable.
Probably one or more of your installed RAM modules are faulty. Test them one at a time (by having only one module installed at a time) using Memtest86 on a bootable CD or USB pen drive. The CD images for MemTest86 V6.3.0 Free Edition are here: http://www.memtest86.com/download.htm
Note: The CD or USB image will automatically make a CD or USB pen drive bootable, you don't have to manually make them bootable.