FIRST OF ALL : RUN THE PROGRAM AS ADMINISTRATOR OR YOU WILL HAVE MASSIVE PROBLEMS !!!
what I do now : Switch Menue On (ALT ) go to WORLD, Scenery Library, ADD AEREA, BROWSE to the AEROSOFT FOLDER in my FSX drive, select a scenery, airport , whatever you have, give it a name in the field aerea title and klick OK. That´s all. When I added VFR LONDON (1.2m Photo ) and London City Airport, both by Aerosoft, I got more then 30 FPS, first time in my fligtghtsim-life, with FSX it´s 11-15 max . Anyway you can run the "PREPAR3D2FSX Migration Tool" by Flight Sim Estonia and install normal. The tool is cheap (11,- EUR) and works perfect. You can use FSX and P3D side by side (do NOT FORGET to switch Virtual FSX OFF in the tool before starting real FSX. I did it for my Digital Aviation FOKKER 70/100 which I love, and for all my PMDGs ( BAE JS4100+MD11+737NGX) everything is perfect. My PREPAR3D license is the "ACADEMIC" . My computer is a mid-range machine : Board Z68XP-UD3, CPU: Intel® Core i5-2500K CPU @ 3.30GHz, 16384MB RAM, Graphics Card NVIDIA GeForce GTX 260, System Drive with Intel Rapid Storage, FSX on SSD Drive but PREPAR3D on a normal HDD ! I will probably say Good Bye to FSX an completely switch over to PREPAR3D ( the name is horrible ) as all my ADD-ONs for more than 1000,- EUR until now work fine.
I apologize for my English, it´s not my native language.
Hans Lauer