WPA.DBL--The Keeper of the Keys
The WPA.DBL file resides in the Windows\system32 directory and holds the hardware configuration information and activation state of the current Windows XP installation. The WPA.DBL file is actually an RC4-encrypted database of the expiration info of your installation, the confirmation of activation, the hardware configuration at activation time, and the current hardware configuration. When you first install Windows XP, this file is approximately 2K in size--not much more than a stub file. When you activate Windows, this file grows to approximately 12K-13K, recording the hardware status of your machine. At each boot, Windows analyzes your current hardware and compares it to the stored configuration information to see if it has changed. When you make hardware changes, Windows makes a note of the changes in the WPA file, but keeps the original configuration for reference. If you make too many changes, Windows XP will reset the WPA.DBL file back to its original non-activated (2K file size) state, and you have to reactivate.
As mentioned above, the WPA.DBL file can be backed up to permit activation if you reload Windows XP. You can also experiment with different hardware configurations, as we did in preparation for this article. You would back up WPA.DBL for each configuration change, so you can roll back whenever desired, similar to what developers may do frequently, as mentioned above. If you save a copy of the WPA.DBL file at each change of hardware, you can roll back to almost any state.
One caveat, from our testing--we found that the WPA.DBL was not protected similar to other system files. If you delete the file, you need to reactivate. The WPA.DBL is also not included in Windows XP's system restore mechanism.