In some systems the WEI "confused" when the graphic card is faulty or overclocked.
Also from general "bad" overclocking.
Bad\faulty motherboard.
And after a HDD firmware update (hard disk not ssd).
(Gigabyte motherboards do this after corrupted bios flash)thats why re recommend the safest way,the usb method.
I know,is strange sample\issue but it happens.I cant know though which exactly is the case for you.
Solutions iv tried? Flash bios (if possible) with the usb method . Stop oc,set everything back to defaults.
You can also check\stress your gpu with
OCCT (the new version is compatible with
both amd and nvidia).
As for the WEI is better to "clear" the experience index.
Follow
Step 3 in this tutorial
Windows Experience Index - Reset