Laptop monitor turns off itself after a minute without instruction?

i have compaq presarionotebook, the monitor turn off after 1 min. i have checked the power options properties, even the power scheme is in "always on" or even if i put the turn off monitor after 30 min or never it doent work, any ideas. i have scaned the sys, no viru or spyware. laptop is one year old, could it be the battery??