The problem is described here BTW: http://forum.avsim.n...to-full-screen/
And this (for FS cognescenti!!) from PMDG support:
"I think it's actually a Windows Driver Model (WDM) problem (which is what's used in Vista and Windows 7) more than it is an Nvidia problem. I've seen the black screen driver timeout thing happen to FS with an ATI card too. A lot of times it happens when you try to run a program that creates a UAC prompt like Active Sky while FS is running too.
I'm not really sure what to tell you though unfortunately because there's documented problems in XP64 with the GTX 4xx series of cards and FS that probably won't be fixed... FS is just getting too old at this point and MS and the hardware makers don't generally tend to fix problems with old legacy software".
Oh dear, oh dear. Maybe I should have stuck with XP. This could be a very, VERY costly mistake!!!