xp pro sp2. about half the time, it doesn't work. i close all open apps, except for the ones in the right side of the task bar. if i go to properties > screensaver tab, and just hit "preview" it seems to work again for a while. i turn off my machine every night, if that matters.

anyone know why or how to fix this?

specs:
x2 4400+
2gb pc4400
6600gt
antec 550w tpII
some hard drives and other stuff