Scenery in FS2002 - again!

Morning all.PC's are like women, just when you think you understand one, it all blows out the window (grin!).For reasons that are beyond me, my scenery, in particular airport buildings and runways, have turned to custard. My machine isn't that grunty, so have the sliders at about 60% mark, but the scenery seems to have lost a lot of it's definition.I haven't mucked around with the sliders, they're pretty much where they've always been, but I'm experiencing problems with making the basics look OK.For some reason, runways/buildings seem to look better at dusk/dawn, when lights etc are on. Seems to me it should be the other way around.Other scenery is OK, just airports, builings, runway etc.I've noticed that when I've set up a flight, clicked on OK, the white slider that appears whilst flight is loading is zipping across in a third of the time it usually does. Previously it took about 20seconds to go through the scenery, AI load, etc., but now it zips through scenery in a flash. Obviously the machine has decided I don't want good scenery, and I need to make it 'un'-decide this.Any ideas would be appreciated.ThanksKiwi