Hi my name is ***** ***** I will be the expert working with you today to help and resolve the problem you have posted.
I am sorry to hear that you are having such trouble. I will try my best to help you out and resolve the problem as quick as possible.
Remove the keyboard driver software from the device manager and reboot the computer by default it will pick US english and then you install German keyboard driver as well and that will take care of the issue.
You will have to select German while typing in German and English while typing in English.