If you try to activate Kaspersky Internet Security 2009/2010 by an activation code for Kaspersky Internet Security 2012, the following error will appear on the screen:

Kaspersky Internet Security 2009/2010
cannot be activated by an activation code for Kaspersky Internet Security 2012.
In order to eliminate the problem, it is required to install Kaspersky Internet Security 2012. In order to do this, perform the following actions:
- click OK in the Kaspersky Internet Security window
- download the distributive of Kaspersky Internet Security 2012 from the official Kaspersky Lab web site
- uninstall Kaspersky Internet Security 2009 / 2010 from your computer
- run the installation of Kaspersky Internet Security 2012 by double-clicking the downloaded ditributive
- follow the Setup Wizard instruction to complete the installation
- restart your computer
- activate Kaspersky Internet Security 2012.