Can you "restore" the BIOS?
No in the way you are thinking of as the BIOS has no way of remembering an old set of instructions.
You can can settings in the BIOS back to what you had before if you know exactly what those settings were.
I suggest you reboot press the appropriate key to enter "setup" at the message (depending on the machine this is usually keys like F2 Del or Esc)
You need to navigate to the settings for the boot order and make sure that boot from USB devices is disabled.