Airplane fails after loading savegame

Some weeks ago I encountered a problem concerning loading savegames.

When loading a saved game, a view of the cockpit flashed up for a very short instance before that fsx-loading screen showed up. When loading was finished, the cockpit was all dark und no systems (not even battery) were working. The green bar, counting down from 20 until the ngx systems are powered up, is also missing.

I reinstalled my whole FSX-System including FSX and REX and everything was fine and working.

This evening FSX crashed to desktop and I finally get that same problem with loading savegames.

Can anyone get me out of this?

Thanks for your Help

Fred

My System: FSX Gold Edition with Accelleration Package installed/PMDG NGX Service Pack 1C/REXessential wOverdrive

Intel i7-2600K @ 3.4 GHz

GeForce 570GTX

Windows 7 64Bit