Nope, you copy the activated version. You can have as many copies on your hard drive as you want.
This way you can also prevent using up your activation keys. After a fresh install, make a copy. After setting up everything, make a copy again. Then if things got screwed up with your install, you can always use the backup copies you made.
The only time you will need to use one of your activation keys is when you format your pc.
(when making a copy, don't forget to copy the shortcuts as well and change the target directory to the new location (right click on icon, properties))