Real Time Rendering not working

Hi,

i think I have a real stupid question. And i am getting really desperate because i can't fix this error. It is probably something really easy to fix.

I installed new Hardware in my PC (everything execpt GPU and Hard Drives). After this I reinstalled Windows and Premiere Pro 2020 CC.

Now the real time rendering is not working. All the Settings in PremierePro are gone (of course).

When i put a layer above my media (e.g. a settings layer) and change something in that, nothing happens to the preview. When i render the section, everything is fine.

Thanks in advance for your help!