Vista screen saver

I bought a new HP laptop a week ago that came preloaded with Windows Vista Home Premium. I also use wireless mouse and keyboard with this. The problem am facing is when I start my laptop powered with AC, my screen saver wont work, neither gets activated. And if I boot the system with just powered by battery, everything seems to be working fine. Furthermore I have set the balance mode "Turn off Display" at 2 mins and screensaver for 5 mins. Any idea what could be the cause for this strange problem and how can get rid of it? Many thanks.

Well dude, to me it sounds like dumb question. I mean, if you have set turn off display at 2 mints and screen saver at 5 minuts, then how can the screen saver get activated after 5 minutes if the display is already turned off?

Ok, I understood what you want to say buddy. Now this is what I did. I increase the turn of display time to 10 minutes and set screensaver time @ 1 mint. But still screensaver wont come. So the problem is still with Vista Screensaver, right?