That means the FIRST thing that happened was a complete wipe of the harddrive IF he didn't take measures to backup your files. The factory restore or system restore makes the pc virtually new as if you'd never saved anything on it. The registry is squeaky clean now, the programs are all factory default, Windows requires updates (if not already done while he had it) etc.,
The list goes on. There's not a trace of data on that PC that remains before you sent it off to get fixed. It won't be found on that PC. He'd have to had extracted your personal files, programs, etc., before doing that. I can tell you now, I doubt he did. The moron.