OK. I uninstalled and reinstalled and re-activated PMDG 737 NGX and I've installed the recommended simconnect interfaces and I cannot get the virtual cockpit knobs that control speed, heading, altitude, range, altimeter etc. to function. Some of these functions are available on the 2D panels and they work OK there. I've found the click spots and know what the grey hand and the white hand signify. The mouse wheel doesn't do anything and left and or right clicking has no effect in virtual cockpit. I am using the most current drivers and the latest Prepar3d install. Any suggestions? I am at a loss at this point. My default aircraft all work just fine. Oh, one more thing. The 2D main cockpit panel (Shift 1) is coming up all distorted and the top part of the panel is scrambled beyond use. I've correctly activated both Prepar3d and the PMDG 737NGX base package and have read and followed the instructions in the PMDG manual. Either I have missed something or I do indeed have a compatibility problem somewhere. Thanks.