For computers that slow you can set them up to do dedicated tasks if you want, like an alarm system
http://www.lowendpc.com/box/2002/0626.html :p
(just kidding; i'm typing this post on an emachines celeron 366

)
P.S. Keep both systems. Right now I have two computers, and hooked them up with a router. I'm sharing files and printer from the emachines to my new computer... if you're a true geek set it up to show off to your friends!
