Studio 1555 Laptop Sleep Mode

I am taking a shot in the dark that anyone can help.

I have an Old Studio 1555 laptop that is very much out of warranty but still operates.  It is running Windows XP but is very capable of running a couple of games that I have loaded on it.  It has always had an issue that I am trying to troubleshot and fix (if there is any easy fix).  When I shut the lid it goes into sleep mode and will not come out of sleep no matter what I do.  My only option is to shut it down and restart.  I have been through every power option setting that I can find, pressed every key combination I can think of on the keyboard, and NOTHING will get it to wake up.  Dell support is no help since it is so far out of it's service life.