Are you saying you installed an application, lost the installation exe and want to back up the installed application?
Anything installed probably will have registry keys and files outside it's own directory (like in the sys dir). Unless you install under an app that logs changes to your system (what reg keys were added, what files were added and where) I don't think you can do what you're talking about.
Maybe if you tell us what application you are trying to back up we could give you a little more information. Just for your information... probably 85% of all applications will not work if you copy the directory and restore it. Sometimes even the smallest programs install hundreds of registry keys and a couple OCX files.
Ep, glad to see you come back and tidy up...did want to ask a one day favor, I want to enhance my resume , was hoping you could make me administrator for a day, if so, take me right off since I won't be here to do anything, and don't know the slightest about the board, but it would be nice putting "served administrator osnn", if can do, THANKS