Lately a lot of people have been posting questions about problems they are having with FSX and/or add-ons they have installed. Comments like "It was working great" and "It just suddenly happened" tell the person who may be able to solve your problem absolutely nothing.
If you have already searched these forums and Wiki for an answer to your problem but come up empty, here are some hints that will help us help you.
1) List your system specifications.
Knowing what kind of components make up your system will help us to determine if you are having a hardware problem, software problem or both. Knowing this information will allow the person who may solve your problem to eliminate possible causes also. So list your hardware; CPU (manufacturer and model), GPU (video card manufacturer, model and amount of VRAM), motherboard (or computer make and model if store bought), and amount of RAM on your system. If you don't know or know how to obtain this info, ask.
2) List your software environment.
Knowing what operating system, what bit version it is and whether you have it up to date or not, will help solve your problem. Also listing what your FSX install is composed of will help solve your problem. Do you have both service packs installed or Acceleration? If not list what you do have installed. Same goes for your system drivers, have you updated or changed them? Do you use popular add-ons for FSX? List them and what version they are if you do.
3) Be detailed as possible about what your FSX problem is.
Tell us or post a picture of what error messages you are receiving. Tell us what happens and what you where doing in the sim when it happened. Did you crash after awhile over such and such place? Tell us where it is and what aircraft you were flying along with any additional FSX related software you had running at the time. Tell us if you have changed drivers recently. Tell us if you have made any changes to your computer. Are you having trouble installing scenery or aircraft? Tell us precisely what you are installing and include the file name or version info also. Info, Info, Info will help us help you.
4) If you are having a problem with 3rd party add-ons be sure and check the developer's forum(s) first.
It is possible your problem is a common one and has been solved. Checking the developer's forum can save you and us time.
5) Be patient.
Sometimes even after discussing your problem a person may not be able to solve your problem. Do not fret most likely someone else will come along who can solve your problem.