If you're happy with the current installation and setup of your operating system, and want to copy it, so you can go back to it at a later time, you need some kind of "disk image" software that can take a snapshot of the drive, and save it to DVD, so you can go back to it quickly.
Acronis TrueImage is a good one (not free) that I've used. The latest version can save the image straight to DVD. But the main advantage of that program is that you can run it with Windows XP!
If you have a spare drive or partition, that you can keep as a backup, you can "clone" the drive, with a program like XXCLONE (free version available) and Ghost.
A Disk Clone program copies the partition, as is, so you can come back later to it very quickly.
XXClone can be used from within WindowsXP.
nLite is something else. It prepares a Windows Installation CD in the way you want it, like removing certain components (print spooler, audio support etc.) that you don't need, and then use the prepared CD to install windows.