About a week ago, while simply browsing the Internet, my computer shut off unexpectedly. Attempts to turn it back on were unsuccessful without resetting the breaker on the PSU. I did the steps from the troubleshooting thread and eventually found that if I unplugged the 12v 8pin connector, the pc would power on without tripping the breaker. Obviously without that, it was doing nothing. My first guess was the PSU so I swapped it with a known good 850w corsair unit. Still popped the breaker with 12v 8pin plugged in. It would do this with nothing else plugged in so I ordered the new mobo. After taking 3 days for "overnight" shipping (ups 's fault), it arrived. Went through the process of changing everything out and then powered it on... No VGA output and no beeps. Thought it might be a DOA mobo but after I ordered another mobo and a 3770k it booted right up. Had to repair windows because surprise new mobo but running strong now. For reference, everything ran cool <50c CPU, <75c GPUs under prime95 even in this Chicago heat wave.
I'm stupefied by this. I've been building my comps since I was 10 (am 26 now), upgrading every 3-5 years, and have NEVER had a component fail that wasn't either DOA or well... 5 years old caps. Also, there was no brownout, power surge, or other electrical anomaly and is plugged into a working surge protector. No loose wires/screws or anything to short the board. Somewhere in that CPU 12v circuit, it shorted out on its own, taking the CPU with it, despite the power supply cutting power (mostly to avoid fires, not save my toy).
I can send the board back to asrock but will have to pay a fee because it's been 9 months since the build, so why would I keep a bunch of bulky boxes??? No dice on them paying for the (at the time) 320$ CPU though. Understandable as a business, they can't be sure I didn't burn it myself (it looks fine, but does not work... Maybe I can send it to intel for testing???). But I've googled a lot and have never seen a mobo spontaneously fail and toast the CPU.
Seems like a rare event, but I would steer clear of asrock as this problem is unusual and frankly ridiculous. Your mileage may (hopefully) vary.