Given that the Registry is an essential component of Windows, and a damaged Registry can make Windows totally inaccessible, a good backup of the Registry is one of the most important safeguards you can employ.
Windows Vista does not come with a distinct mechanism that automatically backs up the Registry, which means you'll have to implement one of your own to fully safeguard your Windows environment.
The Registry is stored in certain files (see the preceding section, "Hives") on your hard disk, so you can create a backup by simply copying the appropriate files to another location.
When you start Windows, the information in the Registry is loaded into memory. While Windows is running, some changes may not be physically written to the Registry files until you shut down your computer; others, such as those made by the Registry Editor, are usually written immediately. For this reason, if you've made any substantial changes to the contents of the Registry, you may want to restart Windows before backing up the Registry to ensure that the files on the disk reflect the most recent changes.
The other consequence of using the Registry files is that you may not be able to simply use Explorer to copy them while Windows is running, and you certainly won't be able to overwrite them. The workaround is to attempt these measures when Windows isn't running, which means using a Vista boot disk.
Although it's very useful to make backups of the Registry on your hard disk, it certainly can't prepare your computer for an actual disaster. If your hard disk crashes or becomes infected with a virus, or if your computer is stolen or dropped out of an eight-story building, those Registry backups on your hard disk won't do you much good. The most effective Registry backup is simply a matter of making a copy of all hives on your hard disk and keeping that copy somewhere other than inside your computer.
If you back up your entire system regularly, such as to a CD, DVD, hard drive, or other backup device, you should ensure that the backup software you use specifically supports safeguarding the Registry. The Registry will fit easily on a removable drive (CD, DVD, flash drive, etc.). In addition, most modern backup software includes a feature to back up the Registry, as does the Backup and Restore tool in Windows Vista.
One useful shortcut is a local backup. If you plan on modifying a specific value or key, it's wise to back up just that key, because restoring it in the event of a problem is much less of a hassle than attempting to restore the entire Registry. See the following section for details.