If you're preparing to install the Microsoft Windows XP operating system on a computer, you must enter a valid product key. This product Key ensures that you are using a genuine copy of Windows XP. After installing Windows XP on computer, you can find your current product key through the system's registry.
• Log on to your system with an account that has administrative privileges.
• Click on “Start menu” and then click on "Run."
• Type "regedit" and click "OK" to launch the Registry Editor utility program.
• Navigate to the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\ CurrentVersion directory using the database tree on the left side of the window.
If you are facing any problem while activating Windows 7 operating system you may take help from windows 7 support at their Toll Free No. +1-866-541-1792