Thanks guys. I'll try repairing with the FSX disk and if that doesn't work, I'll take a look at the video card. The system's only about 15 months old and it's an Alienware, so it should be pretty high quality. I'm just wondering if it's a texture issue, how something got corrupted. That effect has always worked fine and I don't recall doing anything lately to change it, although I did recently buy a few payware planes.
Regards,
LT1