Xylem,
This is strange. MarineAquarium3.scr is in my System32 folder, but not present in the Display Properties Screen Saver list. - Right-clicking/installing from the desktop icon, makes no difference. - In the Display Properties Screen Saver list MA3 is called
SereneScreen Marine Aquarium
I am using Win2kPro SP4, BTW.
Check your DirectX. 9c is the minimum and unless you can work voodoo, Win2000 is the lowest that can accept 9c