You can find information that the installed trial version has expired in the Kaspersky Password Manager window in which you enter your Master Password:
In this window you can also click the link Purchase License Key online. On the web page that will open you will be able to purchase a license that will turn your trial version into a fully functional commercial version.
The web page on which you can purchase a license can also be opened from the Kaspersky Password Manager context menu by selecting Buy Now!
The Buy Now! option is also available in the Caption Button context menu which can be found in your internet browser:
When you click the link Purchase License Key online from the Kaspersky Password Manager window or select Buy Now! from the context menu, the web page with the address http://www.kaspersky.com/after_the_trial will be opened.