On another computer you can download and burn a W7 disk (follow links
HERE) but be sure to get the same version (likely Home Premium) and same bit size (x86 for 32-bit, x64 for 64-bit). I'm not sure what booting to it can do but, it never hurts to have a copy and you can always see what it says.
Generally on the BIOS screen it lists your hard drives their size. What happens if you select that drive in the BIOS?.
BTW, for anyone else reading this, to get to your BIOS it could be F2 or F10, F11, F12, or Delete, or Esc; it depends on the brand computer.