Screen not going blank when closing screen on Dell Insprion 1150

[e24ohm]

Folks,
I have a Dell Inspiron 1150, and I am having a hard time getting the screen to go blank when i close the screen. I reviewed the details under: System > Preferences > System > Power Management. I made sure i had the right settings set under the Battery tab, yet i can not get the screen to go blank.

I am trying to see how much battery life i can get out of my laptop, which has the celeron processor. I switched out the HDD for a SSD drive from Scandisk as well.

All-in-all it runs ok, not great but just well enough to do what i want it to do. *laugh* at 3 kg it is no netbook.

If anyone can shed light on this matter, i would welcome it.

thank you...
Cheers!!!

E