Visual Problems with FSX when using payware a/c

Good evening all, Not sure where to put this, so feel free to move if I made the wrong choice. I recently got a high-end system for an FSX upgrade, but I'm having a big problem with payware. Whenever I load any payware aircraft, the viewable area shrinks to the upper left-hand corner of my screen with ghost images in the areas surrounding it. I can try and post a picture or video if that would be helpful. My FSX has SP2 and whatnot installed and it runs absolutely fine on any default aircraft. I'm operating on Windows 7 64 bit with an NVIDIA GeForce GTX 590 and a 3.4Ghz i7-2600. Graphics card drivers are all up-to-date, same with direct X. I read that DX10 preview can break some addons, so I tried disabling that, but there was no effect. Default aircraft run with no problems whatsoever; the only issue comes up when I load up any payware aircraft. Any and all help is deeply welcomed. Thank you, all!