The COMAND system in my '09 CLS 550 just went completely blank, with no sound or operable functions at all. The power on/off button does not respond either. I can still cycle through the multi function display through the steering wheel controls, but no information is displayed on any of the screens. Just the screen title and dashes (eg; NAVI ---, AUDIO ---, PHONE ---). The only screens displaying information are the Trip Computer, and the Reset screen (which actually did nothing when I tried a reset). I will check the fuses, of course, but wanted to know if there were any other possible causes and/or fixes. I've seen many other owners reports of similar occurrences, but none were quite the same as my experience. Any help or suggestions would be greatly appreciated as the prospect of going to the dealer is financially terrifying.