Recently solved a really annoying problem I had after going through all the normal routes, flushing shader cache, etc.
After deciding to try out Kostas tweaks to FSX including CFG changes, I had the attached screen showing on the free flight screen for all aircraft, this was replicated in game.
Long story short and after following several dead ends, I discovered the problem was caused by having shader 3.0 mod installed and having reset the fsx.cfg file which removed a required line from the config file that shader 3.0 requires.
Simply uninstalling the shader 3 mod and flushing the shader cache resolved it.
As the problem was caused by a missing line from the fsx.cfg which is added in the shader 3.0 installation if one had this problem and then wanted to reinstall shader 3.0 this shouldn't cause a problem.
D