Okay, I guess my translator was a little off when it translated your post. By the way, this is an English Only Forum so next time you reply please translate your post into English, Thanks.
To help you I will need to know your son's computer setup. Make & Model of your Motherboard, CPU, PSU, GPU, Windows and AMD driver version installed, BIOS version currently installed on your motherboard, etc.
Especially the Make & Model of your son's PSU and Motherboard and GPU and CPU and Windows version installed.
Once you post that, Me and other Users can help determine the best way to upgrade your computer for gaming. Plus what type of Budget do you have in mind as far as spending goes? 200 Euros or 500 Euros etc or whatever your country's currency is.
The reason why I mentioned your photo is because it is showing the devil in a Non-traditional way (positive image). (-: .
Which I personally found to be offensive. But that is me only and no one else here at AMD Forums. You could have left it on the post since it wasn't doing any harm if you feel it is something that you agree with or find humorous. '
As I mentioned it was just my personal opinion and nobody else's here at AMD Forum.
EDIT: If you don't know your son's Computer hardware or software download a free program called SPECCY. Run it post it on your next reply. It will show most of your Make & Model of your computer's hardware and software including BIOS and Windows versions.