I built my first rig about 2 months ago, since then I've been experiencing random restarts, blue screens, complete system crashes that I have to restart my PC and maybe that could be the issue why my PC is lagging from time to time though my PC is pretty good, I did the Windows Memory Diagonastic, it said that the RAM sticks are fine. Also, what's the difference between memtest86 and memtest86+? Should I launch one of them, or both to make sure that everything's working and should I test both of my RAM sticks separately (I have 2x4 GB DDR3 RAMs)? Should I try switching the RAM slots? I'm going to do the memtest when I'm going to sleep, should I leave it working overnight? And in the morning, when I'm going to school, should I launch the other memtest on the morning? The BSODs I've had are BAD_POOL_HEADER and IRQL_NOT_LESS_OR_EQUAL.