It sounds easy to solve but I'm completely lost in it. I tried KDE settings: disabled screen saver, disabled monitor power management.. Nothing worked. Even I tried to find something in YAST -- no luck. Actually screen goes black after about 10 mins of inactivity which is annoying while watching in ex. Youtube. Playing Kaffeine is OK - I think it's because Kaffeine makes "fake mouse movements".
Suse 11.3, Linux 126.96.36.199-0.1-default x86_64, KDE: 4.4.4 (KDE 4.4.4) "release 2"
ADM Athlon Dual Core 4450e (2.3GHz), 2 GB RAM, GeForce 9600 GSO 512 with nVidia driver