Installationsprogramm wird nicht richtig angezeigt

This appears to be the license agreement.  Again, try to use the Tab-key to move around the document.  Perhaps use the Spacebar/Enter keys to check any required boxes.

Otherwise, you can try to resize the window.  What is the size and resolution of your monitor?  Try right-clicking on your Windows desktop and choose Display Settings.  In the Scale & layout section, make sure the monitor is set to the recommended resolution and then adjust the scale percentage.

Try pressing the Tab-key to move around the installation dialog.

If that doesn't work, I suggest you contact Adobe Elements support. You can start a chat session by going to the Contact Adobe Support page  and clicking on the chat button in the lower right corner of the page. Make sure you are signed into your Adobe account and try typing Agent when the chat window opens.  That way, you should be directed to a live person rather than go through the chat robot.