Video in Train Simulator

After months of fine operation I have suddenly run into a video problem with Microsoft Train Simulator. Once the problem loads, the text on the opening screen flickers constantly, as do all subsequent screens. Flight Simulator on the other hand works flawlessly. I even reinstalled Microsoft XP but the problem continues. All other programs seem to work fine. It looks like large polygons turn white, then return to normal mode then turn white again. Also some elements of the screen seem to flicker while others are unaffected, although there appears to be a randomness to it. I have an IBM NetVista with TFT screen. Does anyone have a solution????