No matter how much time, you've had building and troubleshooting computers, there's always a curve ball. Read and learn 2 months ago, my system started to lock up consistently after 2-10 minutes after booting. If I was working on it, the mouse would start to lag, then a few seconds later, completely unresponsive. I even had it lock up in a BIOS screen, even before booting into Windows!!! Here's what I tried, and each attempt met with no luck: Swapping the video card Swapping the memory Reverting to stock clocks CMOS Clear/reset Unplugging all storage peripherals (Extra HDD's, floppy, CD) A different boot HDD drive Monitoring the power draw (PSU) Finally, I replaced the MOTHERBOARD!!! Had a Maximus Formula X38, replaced with a Rampage Formula X48. Well, thought that was all good. but nooooo... About 15 min mouse studder, crash and blue screen. Rebooted and 10 min later locked up in windows like before. So I was scratching my head... ok - doing this: I happened to have a spare keyboard lying around ( prodikeys of all things). Took out the old keyboard and put in the prodikeys... It's working!!! So here was the root of the problem: Go figure, a $15 keyboard was the issue. Lesson learned? Perhaps. And that lesson would be this: before replacing $100's worth of parts, start with cabling, then try to root out the cheap stuff.