Ask the Doctor: Everything is Broken

I built a computer for a friend a couple of years back, and it was working fine until a few weeks ago, when the computer started to lock up on boot and the screen would stay black. I tried to reinstall Windows XP, only to have it freeze halfway into the setup. Eventually I was able to reinstall XP. All case fans, the CPU fan, and drive lights work fine. I updated video drivers, replaced the videocard, the memory, and the power supply, and even switched out hard drives; the system still locks. I’m at a loss for what to do next. I suspect maybe the mobo is at fault. Can you help?  —Howard King  Read on to find out the answer to Howard's question! read more (link)