WIndows 7 Screensaver not going off!!?

My screensaver is set to annoy and frustrate me. I have selected -None- and I have put the time out to 50Minutes, but after I click Okay; the parameters reset themselves back to -1M- timeout and the screen savers come again after 1 minute. I have tried 1000000 times to put it off, but it keeps going back on by itself. My computer is a Windows 7 Acer