How do I stop my MBP from going to sleep?

I'm a new mac user/this is my first mac. I got 3 wks ago. When I'm using it (both in OS X & Win XP) when I leave it on with no action (such as moving the mouse) the laptop keeps falling asleep. How do I make the laptop stay awake both in OS X and Win XP when I have to leave it for some time (such as to go kitchen and eat supper, go to phone in another room of our house to talk to a friend who's returning my phone call, etc)?


I keep the MBP in our dinning room on its own computer desk in a corner of the dinning room.

In OS X...you would go into systems preferences, open "Energy Saver", click on the "Show Details" button, and adjust.

In Windows you would go into your "control panels"...find the proper utility (I think it's called "Power Options"), and adjust.

Hope this helps,

- Nick