Legally you can use same install CD, but you have to buy a license for each computer intalled on.
Of course, you can install anyway, and just call them requesting another Key since you upgraded to get around this, but not legal.
<pre><font color=red>°¤o,¸¸¸,o¤°`°¤o \\// o¤°`°¤o,¸¸¸,o¤°
And the sign says "You got to have a membership card to get inside" Huh
So I got me a pen and paper And I made up my own little sign</pre><p></font color=red>