Most manufacturers are starting to place the key onto the CD and running a Admin install so that you bypass the key entry. Specific CDs for specific manufacturers will have a tattoo on the hard drive as well. Ran into a couple issues with warranty work for customers on HPs. They need the tattoo installed before reinstall on a new OEM hard drive.
What manufacturer do you have? Dells always use OEM CD, compaq and HP are pretty picky as far as what CD you use.
