Then see if there is a program installed on it, by eMachine, that will actually use a hidden partition that stores all the factory settings.
If so, you can use that program to recover your computer to its factory settings.
If there isn't one, and you don't want to spend the money for recovery CDs, then you can simply format the hard drive to remove your information and have the person you're giving the computer to install their own operating system.
Those seem to be your only alternatives.