No, you cannot legally installed that OS on more than one computer.
The only way I would see it is if you would destroy the original PC. Legally you own the license.
Had a client that ran over his PC
(don't ask, long story, funny but long
). We built him a new PC, believe it or not we salvaged just about everything except the DVD and the case. So when we reloaded the hard drive with XP (he bought a bigger one, but not because he needed one) we used his license from the "old" PC.
You are right, it would be illegal to have the same license on more than one PC, but as long as you destroy the first one, you should be OK.
-Carlos: