JAY: "OEM versions of vista pre installed by HP, Del and others will have two keys. The key that software like Produkey (that's what I used!) find is the OEM SLP (System-Locked Pre-installation) key linked to the motherboard. But OEMs are required to also include a valid COA license with sticker. It is this product key you must use when doing a reinstall of vista not the one your software shows as it will never activate."
http://www.technibble.com/forums/showthread.php?t=17808&highlight=microsoft+product
Alan22: "Many years ago Microsoft stopped allowing Branded OEM license keys from activating Windows installations via the Internet. People were going to retail stores, writing down OEM license keys from the COA sticker and using them to pirate copies of Windows, whether on their own single system or on multiple systems. This is just one of Microsoft's efforts to combat piracy. In some cases the Branded license keys can't even be used to install the OS.
So, the COA found on Branded OEM COA's should not work to activate Windows via the Internet, especially if not using the correct, Branded OEM Windows installation disc. To properly reinstall Windows on a Branded OEM computer system the manufacturer's installation disc should be used (i.e., Dell for Dell, HP for HP, etc.). These Branded OEM Windows installation discs should be pre-activated and should not require the end user to perform any type of activation. Plus, the EULA's are different from regular OEM, upgrade and full retail EULA's.
I've installed Windows I don't know how many hundreds of times over the years and I always use the correct Branded disc for the computer I'm working on. I've never once had to activate Windows in this scenario. In addition, I've also performed hundreds of upgrades and fresh installs via regular OEM, upgrade and full retail discs. In each case those needed to be activated either by Internet or phone. Some didn't activate over the Internet, but a call to the activation center results in obtaining an activation code. You first need to go through the automated phone process, then when it fails you're transferred to a live person who can provide an activation key (after answering some questions)."