What’s the best way to flash my BIOS using a USB stick?

If booting into safe mode is your only option, I suggest addressing that issue first before messing with the BIOS. Safe mode usually indicates problems with Windows itself rather than hardware issues. If you're thinking of a BIOS update, check your motherboard documentation for specifics on how to do it from a USB.

You're right to think of updating the BIOS, but if you're facing boot issues, it may not be the underlying cause. To flash your BIOS, boot into the BIOS settings—most motherboards have an option right on the main screen or in a 'boot' or 'update' section. Make sure to follow your motherboard's instructions for using the USB stick.

Flashing your BIOS likely won't solve the issues with Windows, especially if you're only getting into safe mode. It's usually better to focus on resolving those Windows errors first. Once you're in safe mode, make sure to update all your drivers and run a system file check to fix any underlying problems.