Yes the license key is tied to the disc I'm sorry to say.... have a look
at this link 'MS Support'
(
http://support.microsoft.com/default...B;en-us;326246) there
might be some help for you.
One thing you can do with a scratched disc... is to get some metal
polish like Silvo or Brasso... the fluid kind not the wadding type, with
a nice soft clean duster, polish and polish keeping using a circular
motion over the entire disc, eventually the scratches will come out,
keeping a little on the duster.
I have rescued many a dvd and cd that has become jammed and scratched
in home entertainment units I've had in for repair, I get folks what
think they can put them in and treat them any old way.
The data is not written on the outer surface but under the top label
which acts as a reflective surface.
Again, the secret is using a circular motion and keeping the disc on a
flat surface so as not to warp it whilst polishing... and don't be
afraid to use a modest amount of pressure evenly.
Some good advice is any important disc always burn a copy and store the
original in a safe place away from the computer, also keeping a cloned
copy of the hard drive helps, as you probably aware reformatting and
installing an operating system is peanuts.... but seems to take at least
a full day to get all the programs back, with a cloned disc you can
simply swap the drives over and carry on.
davy