what if pressing command and r does not work

[Mic___]

Trying to factory reset

 

[mrmez]

Holding command-r does not do a factory reset, just starts the recovery program.
If that's not working for some reason, start holding option instead. You can select from there.

 

[BadAsAl]

If you are on a MacBook it is possible the keyboard is bad, try a USB keyboard. If you have a non-Apple USB keyboard then use the Windows key and R.