Disable the Self-Defense. ^1
Close your Kaspersky product.
Click on 'Start Reset' to begin. ^2
Wait for Kaspersky to prompt you to activate.
Activate your product using the online method.

Notes:
The location of Kaspersky's 'Self-Defense' may vary depending on what version of Kaspersky product you are using.If the removal of the old license key failes then log off or restart your computer and try again.

Change Logs:

v2.3.0.0 Final - June 12, 2009
Fixed the ’settings load’ bug

v2.2.0.0 Final - June 05, 2009
Added option to customize the resetting method
Added option to configure the updates
Increased the application startup speed
A few GUI design modifications
Fixed the startup bug

v2.1.0.0 Final - May 27, 2009
Added a new Graphical User Interface
Added auto-enabling for Self-Defense
Improved and perfected the resetting method
Added multithreading support
Other small adjustments

v2.0.0.0 Final - May 03, 2009
Added support for future Kaspersky products
Added a ’Frequently Asked Questions’ area
Added the ’Check for updates’ function
Added the ’Send Feedback’ function
Rewritten the resetting method
Numerous adjustments.