Before I go on, this will only work with manufacturer installed Vista installations. If your laptop is from HP and HP installed Vista then that is what is considered an “OEM activation.” When performing a clean install it is possible to backup your OEM activation and will prevent you from having to call Microsoft for a new key.
In some cases, the key on the Certificate of Authenticity (COA) is not the key that was used to activate Vista. This makes sense because it would be foolish for a manufacturer to activate every single copy of Vista installed and so Microsoft gives them permission to activate many systems using OEM activation.
You can try using the key on the COA but that’s no promise it will work, it has not worked for me more times than it actually has. So, I was left calling Microsoft and hoped they were kind enough to understand my situation, they were but it’s still totally unnecessary.
At this point, I will tell you this utility is not to be used to pirate copies of Vista and it probably wouldn’t work and it would be illegal to try.
Having said that, go ahead and boot into the Vista installation that you want to reinstall. Now, download the Activation Backup and Restore utility available near the bottom of this page (or just use “Find” in your browser to locate the term), unzip it to an external flash drive and run the “activation_backup” file.
At this point it has created two additional files for you, one containing the actual activation backup and one containing the key that was used to activate that copy of Vista.
Now you can boot from your Vista restore disc or Vista recovery disc and begin installation. IMPORTANT NOTE: DO NOT enter a license key during the installation, skip that step. It is imperative that you NOT enter a license key and MAKE SURE to uncheck “activate when online.”
After the installation has finished, plug in the USB drive containing the activation backup, run “activation_restore.” It will now attempt to restore the OEM activation that was performed at the factory. So far, this method has been most effective for me in restoring the Vista activation.
Note, it may take a reboot before the Control Panel reports Vista as activated.
I have not confirmed whether this method will work on copies of Vista that you personally installed yourself as it was only intended to restore the OEM activation from a factory install.