If you have a Windows XP Service Pack 2 that displays the message ‘for testing purposes only’ in the bottom right corner, you can follow these simple steps to remove the message.

Go to Start, Run and type regedit. The registry window will open. To remove the message you have to find two keys and delete them. Navigate to this location:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SystemCertificates\ ROOT\Certificates and delete the Key: 2BD63D28D7BCD0E251195AEB519243C13142EBC3

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SystemCertificates\ CA\Certificates and delete the Key: FEE449EE0E3965A5246F000E87FDE2A065FD89D4

This type of service pack is designed as technical preview and is published for IT professionals for testing purposes only, hence the message in the corner. It is not intended for production environments and there is no support from Microsoft.