PMDG 2D Cockpit Screens problem

On the PMDG 737NG package, i found that when i installed the base package of 737-600/700 and then the 800/900, i found that if i just had the 2D cockpit view on either the 600/700 when i flew, the screens don't work, but if have just 2D cockpit view on the 800/900 its fine, to get the screens to work on the 600/700 i have to pick 2D and Virtual cockpit, this is a pain as sometimes i like to have loads of weather (clouds, thunderstorms etc) which puts alot of strain on my pc as it is without needing the VC, im quite new to this forum so if this is not in the right place i apologise