To boot into the BIOS you need to press the magic key quite early during boot, for example when the screen says something like "Press Delete to enter BIOS setup." . Details vary per maker and model, so check the user manual or the motherboard manual. That's long before Windows starts. If it works, it proves the hardware is OK.
To boot into Safe Mode, you boot into the recovery drive you made (highly recommended to make one in Windows 10) or into the Windows 10 install disc or stick you can make on another PC with the Media Creation Tool (google that). Since these use nothing of the current Windows install, if it works, it proves it' a Windows issue. Then system restore or repair or reinstall should solve your issue.