This problem is rampart in the internet but all the answers are sketchy at best.
What I found out is this: the original windows software that came with your computer will not be able to install in a new hard drive because it is imbedded with proprietary software from the computer manufacturers that identifies your computer as a sony, hp, dell, etc. And the manufacturers put these codes in the cd so you cannot use their software that came with your purchase to build a new computer.
Fortunately you can download a clean windows 7 from mydigitallife.com, burn it into a cd, do a fresh install, put your code from your purchased laptop, and then load the proprietary softwares from your manufacturers. I hope this solves this once and for all for everyone and will prevent some from purchasing a new set of installation cd's from the thieves.