After installing Windows 98, the Fifa games' (99 and 2000) graphics are all messed up!

When I edit something with FED, then start Fifa and play a match, the pitch and goal nets (in Fifa2000) look really weird. In Fifa99 the players look like aliens or something after editing.

But if I turn off the computer, turn it on again and start Fifa, it's all back to normal!

Has anyone else had this problem or does anyone know how to solve the problem?