Jetline Systems is a good start, and they also make recommendations on which pc works best, but I find the cost in one of their lower end systems a little too much.
Been flying flight sim since the early days and stayed with FS2004 because of my last system and capabilities. Now ready for new pc and one that is Intel i7-6700 Quad Core 4GHz and unlocked for overclocking to 4.2GHz, good if not great NVidia 2GB card, 16 GB RAM and 1TB/8GB Solid State Hybrid drive on Windows 10 Home 64-bit. Will request Windows 7 Pro 64-bit when purchase. Found this system which seems to be designed for FSX at well under $1,000 price on Amazon.
from CybertronPC Palladium 950C
I welcome opinions on above system, again it is under $1,000 and should be upgradeable.
Cal