install Windows into a new folder/directory

Tom called about installing Windows into a new directory...

For testing, as well as performing a clean installation, my preferred procedure is to:
boot to a diskette or CD...
create a folder called "boot"...
copy all files on the root of the hard drive to it...
rename the "progam file" folder/directory to "oldprog"...
rename the "windows" folder/directory to "oldwin"...
and delete all files on the root of the drive.

The Microsoft website has instructions on how to "Perform a clean install of Windows XP".