
There are several types of copy protection, and the point is to make sure the
user is using a legitimate copy.  The simplest and virtually fool-proof way is
for the program to somehow fixate itself to the machine it was installed on
(some sort of checksum, serial number, whatever) so a copy put on a different
machine (NOT installed from original disks) will not work.  

The program is definitely backupable, if restored to the same machine (depends
on the programmer...  don't use a disk drive characteristic!)  If the user 
did an upgrade to the machine, he/she should reinstall all programs any way.
No document look-up, no disk wear-and-tear!

I did not say that the originals would allow only one install.  The user's 
conscience should do that.

I know, I'll get flamed for this...  But with the increasing number of "casual"
users who either unknowingly or don't care about the software copyrights
(It's the truth.  I have "friends" who ask me for copies of my latest games
all the time, and when I refused, they went after somebody else.), casual
pirating is becoming more of a problem.  Some sort of copy protection will
discourage the casual copying.  I've seen what some of my "friends" dug up
somewhere...  Latest and the greatest games, all cracked, WITHIN days of actual
release!  You know how many bytes you need to change in X-wing to disable
the quiz?  TWO!  Yes, TWO!  (And don't ask me which ones they are.)  Determined
pirates are unstoppable, given enough time, but their results do not spread 
that far, since pirate boards are not that well-known, and easily tracked once
found by authorities.  It is the "casual" pirates that the copy protection is
determined to discourage.

What I believe the companies should do is implement the above plus
a special patch once the user registers that loudly exclaims upon bootup
"REGISTERED TO XXXXX -- address, city, state zip" and disables the above.
Two benefits: 1) encourages registration, 2) cuts down on pirating and
makes it more traceable, because if the patch's registration message is
encrypted, it will be quite hard to change, and therefore provides a
stable trail of who allowed their copy out of their hands, and thus
violated their license agreement.

This way, the legitimate users who does not register will experience minimal 
discomfort (who does major upgrades to their computer frequently?) as only
problem they have is they won't be able to restore to another computer.

The registered users would have proven they are legitmate users and therefore
gains full rights, and can restore to different machines.  On the other hand,
the software company now have a record of where THIS particular copy is 
supposed to be.  If this user's copy was found to be somewhere it was not 
supposed to be, we know who has broken their license agreement.  Of course,
a hacker can break that eventually, but that's not the point, is it?