Usually the Medion computers com with two disk.
1. Recovery disk this has a copy of the OS for a clean install.
1 Application and support disk, this is the one that uses the recovery files on the recovery partition. Check if they have this disk.
If it's a newish Medion computer you can start the recovery by pressing one of the F keys on boot up.
I am not sure of the Medion MT6, what OS it has or when it was on sale could be known under different numbers. You could try the Medion & support site click here they may be able to advise.