My experience is that these types of issues are the hardest to diagnose. It could be a variety of things. It almost seems that there is something that is failing, but not quite failed.
One question I have is why you are scheduling to reboot nightly?
Try the following 1st: Download CCleaner, http://www.piriform.com/ccleaner
and run the analysis/cleanup, and also run the registry cleaner until all problems resolved (It may take more than one pass)
Secondly, Download memtest86 http://www.memtest86.com/
, and run that overnight to see if any errors show up.
Alternatively, run your system with one stick of RAM at a time (figure out the primary slot from the MB manual). Try 1st module for a while, if problem persists, try the 2nd module.
Third, try switching the SATA port that your SSD is connected to.
also check the SMART status, and because you have an SSD, it wouldn't hurt to download and run Crystal Disk Info http://crystalmark.info/software/CrystalDiskInfo/index-e.html
Check firmware version of your SSD as well.
After that, you may have to start swapping out parts.
Try swapping the PSU 1st. That should be easier to come by.
2nd, swap the memory
3rd, if you can, try to find someone else with an FM2 socket processor
(you'll need to have some thermal paste handy, as you should wipe clean the old and apply new)
If you can't get another proc, try opening a ticket with AsRock on your MB, and explain what you've done to troubleshoot. It could very well be the board itself.
Hopefully you are still under warranty with them being a recent board.
Another thing to possibly try is a clean install of windows, or attempt a repair of windows. With all that rebooting, the possibility of the OS being corrupted is possible.
Perhaps a failed update that may have altered the shutdown process.
Does the problem ever happen after a shut down and restart?