PC goes sleeping when playing with joy

Hi, well the problem is that i play some games with my joypad..like 2k9, Virtua Tennis 3 and MotoGP 08. When i play like 10 minutes , not tuching keyboard or mouse , just playing with my joypad, my pc (or just monitor) goes into sleep mode, so my monitor turns off and i have to push the mouse or hit my keyboard for monitor to turn on again..
Can you help me?
And yes i got all drivers instaled.

EDIT:
Dont want to wake up the theat.. but Thanks man, it worked

Last edited by Eich on Sat Dec 27, 2008 6:35 am, edited 1 time in total.

Find your power management settings for your monitor and set it to "always on."