Not much info about get into your model in Youtube. You can buy tools for opening laptops etc on the internet and they are cheap, Just in case you are going to make a habit of opening others. Most not much good mind you maybe because i always go for the cheapest.
I take it you are dealing with Medion through the UK and not Germany. Like I have said I am using a desktop with no model number etc on it or on the booklet. Medion were unable to find it either. The model number world probably have been on the box it came with. But I do not hold on to boxes they take up to much room.
Oops think I maybe getting mixed up with Eset and not medion for UK contact.
Not sure if they have an English forum or not.. I think if you use the German Forum you can choose which language you want to use.
Best of luck hope you get it sorted methinks I must have got this desktop the same time as you got your Laptop as Asda's no longer sell them since then and that's where I got mine.