Q: HELP! Reset password: terminal won't work: no volume to select. New Mac Pro: never used! So don't need to save any data.

New computer--MacPro. Bought around 90 days ago. Created a password--can't remember it now. Argh. Moved from US to new country--have no Apple Support access here. Have tried to reset password using the Terminal as suggested on forums. But, no volume to select--the box is empty. Now what? Please help...