I have a 20'' iMac with a 2.4GHz Core 2 and an HD2600XT. There are light vertical wavy floating lines visible on the screen when running Windows XP. They are more clearly seen when you look the screen at an angle, from down below you look upwards to the screen. The floating lines can be precisely seen on grey backgrounds. These lines are not noticable much, but when you closely look with grey backgrounds, they are visible. The problem is very strange because I've tried updating the drivers to my HD2600XT, and no luck at all. I'm not able to determine wether the problem is hardware of software related, due to the problem not existing in Mac OS X. Help me please!