>I'm buying my girlfriend a new PC and it will come with XP Home pre-installed. Is there any way for my to know whether her 4 year old daughter's CD games will work? (Barbie, My Little Pony, Winnie the Pooh, etc.)

Well, what OS are they designed to run under? XP is really slick as far as compatibility goes. If there is an app that isn't working right, the properties of the EXE will have a "Compatibility" tab that you can fiddle with, and even emulate previous WIndows OSs.