I had a strange problem earlier when i was running on bios F15q, i'm not 100% sure if it was a bios problem but i'll point out what the problem was.
I was installing a new graphics card today which is a 7970, thats pretty straight forward. About 20 mins after i installed the card the computer just went off by itself to a black screen, it just went off instantly, i heard the click from my PSU which always happens on shutdown as Corsair PSU's do that.
Anyway, i started the pc back up without a problem, 5 mins later i got a warning pop up on the system tray saying "A USB device has malfunctioned and exceeds the power limits of its hub. You should disconnect the device". Hmmm whats going on here then, i did 2 things. First i uninstalled the USB hub driver and restarted the PC, windows then installed the driver again. Secondly i switched off the PC and did Q-Flash and flashed the bios back down to version V14.
Touch wood ive not seen this problem since, i never had that problem before V8 which is what i used previously, after that i went to version V14 and again that was fine with no issues, i put F15q on then had these problems today, like i said i'm not 100% it was the bios version thats at fault but its odd i never had these problems before F15q and havn't had them since i went back down to V14. The items i use in the USB ports have always been plugged in there and have never moved, nothing has changed other than switching bios versions.
Ive just read on overclock.net that other people have had issues on F15q like the bios isn't holding the overclock settings, mice and keyboard issues etc. After reading that it sounds like mine could have been a keyboard or mouse issue with F15q, i only have 3 things plugged into the rear USB ports and they are a Logitech keyboard, a Logitech wireless bluetooth dongle for my mouse and my wireless wifi adapter, they have always been plugged in there with no previous issues on the other bios versions, the problems seemed to happen on F15q.