Questions about closing the top on a Dell Studio 1737

I have a new Dell Studio 1737.
When I close the top down and open it later, usually the unlock screen appears and I can go back to doing whatever I was doing.
Sometimes there is only a blank screen and I can't do anything but unplug it and remove the battery so it'll start up again.

Should I be closing the top down or not?
And why doesn't it always start back up when I open it?

I'm trying to conserve the monitor life since my mouse won't allow a screen saver to come on automatically; and that's okay.

Thanks.

p.s. Thanks for moving my thread to the right forum. I'm new on this forum and wasn't sure where to post. Now I'm on the right track. Thanks again.

 

If you go to the Windows power options (the battery icon in your taskbar) and change the settings for your power plans, go to the power buttons and lid category, and set shutting the lid to "Do nothing". When it's set to this, the display will shut off when you close the lid, but the system will not shut off or go to sleep.

 

Thank you so much.