I haven't built an Intel based PC in a few years, so I don't have real insight or solutions for you DIJ. However some basic thoughts do come to mind.
Take your computer to the tech/store that sold you the CPU/MoBo combination. More than likely they will give you
SOME kind of tech support for free (your attitude going in is ...it's not broken, I just need some pointers
) because thats just good business sense.
With regards to flashing the BIOS. Usually a good idea. Please
DO read and reread the simple process (step by step) at the MoBo's manufacturer's website before you do this. If you make mistake while flashing your BIOS you'll end up with a brand new desktop paper weight
Please also understand that since your CPU/MoBo combination has already been OC'd (overclocked) and that the settings to create this overclock reside in the BIOS (on all newer MoBos), that flashing your BIOS 'may' restore the original factory values. Thus requiring you to go into the BIOS setup and and reselecting the OC'd values. Be prepared to call the tech/store that sold the OC'd combo to you and ask for the OC'd BIOS settings. If you wish to run it as OC'd, that is, otherwise it will probably run at OEM stock (if flashing restores the default values).
Lastly (my rant)... I'm assuming that they sold you a CPU, MoBO, system memory, video card and a CPU cooler all preinstalled together -right? If later on when you get this beast up and running, the Windows operating system starts to become unstable after about 15 mins to 1 hr of use, look at your temperatures (CPU, MoBo, ambient case) as the potential source. 'Cause I just can't see selling an OC's combo to someone without considering their PC case size and cooling system in the equation.
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...Apocalypse meow