The reason for this thread is because of my experience today. So I was at my internship at my school doing desktop support. One of the computers we had to fix was a computer that crashed and turned itself off whenever it tried to load Windows. It got past the BIOS screen just fine. That is until it started loading Windows 7. So the first thing we tried to do was replace the memory modules with a known good one, that didn't work. We then tried to put in a hard drive with an operating system on it just so we could at least get something to boot. That didn't work either. Guess what the fix was? Unplugging the original system hard drive, probably because the PCB was bad, along with replacing the system memory with the 2 known good sticks that we used before even though we thought it wouldn't fix our issue. I know issues like this are common, but this is the first time I've ever seen a computer with a potential two points of failure. It could have been that the memory slots were just bad, but we put a new stick of memory in a slat that wasn't used yet and that worked.