Hi. I have Gigabyte Z170x gaming 3 eu rev 1.0 mobo. It was working just fine for a year and now after f20 bios update I get bsod "unmountable boot device" then pc restarts, beeps 4 short times and enters bios. Then I reboot pc and everything wokrs fine. This thing repeats once every day at computer start after beeing off for 10+ hours. I tested it memtest86 and no errors were found. I have Windows 10x64, ddr4 kingston furry X 2x8GB 2666mhz, i5 6600k (non overclocked), m.2 samsung ssd, toshiba ssd, gigabyte 1070 xtreme, psu corsair rm 1000 (baught used). How to test is what really is happening?