Laptops :: how to prevent my laptop from going to sleep mode?

Hi, I am running DSL 2.0 LiveCD (no harddisk install) on IBM Thinkpad T20 with 128MB RAM and 700MHz processor. I want the laptop to keep running and not go to sleep.This is because I want to use it as a SSH server for a day. Is there some settings that I can tweak to prevent it from going to sleep? I am a newbie to Linux and any help will be appreciated. Thank you.

original here.