How to fix a malfunctioning MMI in an Audi A4?

I am facing issues with the MMI (multimedia interface) system in my Audi A4. The screen freezes frequently and the sound system doesn't work properly. How can I troubleshoot and fix this issue?

First, try resetting the system by holding down the power button for 10 seconds. If that doesn't work, check for any software updates on the Audi website. If the issue persists, you may have a hardware problem and should take it to a certified technician.