u/morequeso_

MSI Z97 Guard Pro
Intel i5-4460
EVGA 1080

Bought a second-hand PC a few months ago which worked fine until it started crashing during certain games (all fans went to max during crash). Anyways, other reddit threads suggested updating BIOS before buying a new psu. Used M-Flash to update the BIOS, but windows wont boot now. I remember having to reformat my hard drive in the past in order to enable UEFI & secure boot. After updating, I noticed that the BIOS was set to Legacy + UEFI instead of UEFI. In my BIOS theres also something about windows 8/10 compatibility that was disabled after I updated. Am i missing something?

I was thinking of booting from a USB but then what?