For my development, I am using an ATI radeon mobility m6 (laptop yes) since I dont have visual c++ 6 on my desktop pc which has an nvidia. There is no problem when testing my applications on my laptop, where everything works fine. The problem starts when I test them on my desktop pc (and on a friend's one btw), where there is no lighting enabled! I use 2 colorued lights to test them, so it must be obvious. Any ideas? Code is not changed from pc to a pc.