The most impotent thing in a operating system is it’s Registry. Registry contains all information about the changes you made in your computer. If you make wrong change in your system registry that may corrupt your total operating system.

Before you make changes to a registry key or sub key, I recommend that you export, or make a backup copy, of the key or sub key. You can save the backup copy to a location you specify, such as a folder on your hard disk or a removable storage device. If you make changes that you want to undo, you can import the backup copy.

These steps are applicable both for WINDOWS7 and WINDOWS XP

Simple steps for taking your windows Registry backup
NOTE:You must be logged on as an administrator to perform these steps. If you aren't logged in as an administrator, you can only change settings that apply to your user account.

• Open the Registry Editor by clicking the Start button , go to the RUN box, or press “start button+R” then type regedit and pressing Enter. If you're prompted for an administrator password or confirmation, type the password or provide confirmation.

• Select and click the key or sub key that you want to back up.

• Click the File menu, and then click Export.

• In the Save in box, click browse and locate the location where you want to save the backup copy to, and then type a name for the backup file in the File name box.

• Then click OK.

Now you have a copy of your Registry file in your hard drive. If you want to undo your change just click on the backup file and restore them. For more information on Registry backup click here.