KIS 2010 will not allow license key activation using key file.Here is a way to activate using key file

1) Download the key file from personal cabinet or zip file in email and save it to desktop.

2) Turn off Internet Connection.

3) Click “License”.

4) Click “Activate new license”.

5) Enter the Activation Code.

6) Click “ok “on the error message dialog box.

7) Browse your downloaded key file. (Step 1),turn on your internet connection and click activate.

Activating KIS 2010 during installation

*First time users of KIS 2010,please note that you will be prompted to activate KIS 2010 during installation.

* Click on radio button “Activate Trial License”

*Disconnect Internet connection.

* An error message pops up and you get an option to activate using key file “Browse”

*Click on Browse and select the key file location

*Turn on Internet connection and click on Activate

KIS 2010 license key renewal

You can use same method to renew your license.Just click on the red X mark in license manager and  delete the old key file

Follow steps 1-7 to renew your license key

At any point of activation if you get an error “KIS key not compatible with this application or license code exceeded the allowed limit” check this post  How to fix Kaspersky Internet security 2010 Activation Errors? for a fix