Accidently lost Admin right on my cash register

A Dallas Key just sends its code to the till, which then logs on the appropriate user. There's no magic master key.

ok i shouldnt remove the right on that dallas key
do you think I should open the cashe register in order to try to factory reset or even to see if there is a hard drive?
there is a hidden reset button, but even when i keep pushing its only a simple reset...

I'm sorry, but I have no idea. If it's got a hard drive then it's unlikely to have a reset button. The software might have a function to carry out a factory reset, but you ought to ask the person you bought it from.

alright , thx for your help