I've installed UEFI bios update on my Gigabyte GA-Z68M-D2H. Everything went okay, it told me to turn off my computer, plug out power cord and turn it again to finish installation, I didn't plug out power cord just turned off and then on my PC, after that nothing works, no video output, nothing, it's a black screen. I tried to reset cmos, took out battery for couple of hours, shorted clr_cmos pins with screwdriver but it has no effect at all. I really, really don't know what to do now. Can someone help me, please?