This is an interesting discussion we have going here, although I am amazed that no-one has brought up the point that you should'nt even be allowed to purchase System Builder discs over-the-counter.
And Crunch, if indeed these are valid System Builder discs that you have purchased, I wouldn't be surprised at all if there are NO licenses in that package.
System builder discs are used by manufacturers (Dell, HP, Asus, etc) that sell pre-built computers with Windows pre-loaded. The discs are used by the manufacturers to create master images for the machines they sell, and they then put the license stickers on the back or underside of the computer. They save money this way by requiring only a few master discs, and then all they do is purchase (in bulk) the licenses they require. And if per chance a manufacturer does include a set of discs with their computers, then you will likely notice that even though Windows has been pre-loaded, the discs you get with a pre-built machine are still in sealed packages, and have never been used before. The answer is simple: They used System Buidler discs with a master (or pre-activated) key to load the computer with Windows, then give you a single-key OEM Disc to use for re-load later, if needed.
Legally, the only way that you can be in possesion of System Builder discs is if you are a Microsoft Registered system builder.
My advice to you would be to go back to the store where you purchased the discs, and have them provide to you the proper Windows discs, intended for retail sale. Unless, of course, you ARE a System Builder, and make your day-to-day living building 20-odd computers a day for customers...