The previous owner put the mac mini to Windows and erased a standard system recovery. Now is not the work of the team
Command (⌘)-R, Option-Command-R or Shift-Option-Command-R and others. Reset mac os, which was in runoff. Wanted will be updated over the network, but these commands still do not work. Only works to select a boot partition (win or mac if you hold the option). Formatnut section in Windows is also not understood as to one section. Standard system restore will not return?
If you have an old Mac, then it should not be Recovery. Put the system with the fact that God sent, pre-formatted disks. Then updated to latest from those available. But if I'm not mistaken, for the miniks 2006, which were 10.4, the maximum is 10.6 — not sure that there is also Recovery is. In General, let the old man have to die. Put on the shelf, swipe the dust while cleaning, show guests... don't torture him already.