hopefully basic--ground texture really blurry or blinking

Hello,I looked at the pinned threads and couldn't find anything on this. forgive me if this is REALLY redudant.My ground textures are really weird. below say 5000ft, the texture would be really pixelated and appear to 'flash'. If I mess around with the mip map slider, it would go blurry.I remember having this problem in the past. I had a GeForce FX5600 ultra, and I upgraded to a FX5900SE, and the problems started again. I know it's either a FS2004 setting or my driver settings.can anybody point me out in the right direction?thanks a bunch.-Chaz