If you enjoyed Warner Brothers' animated adventure Happy Feet, add the little penguin to your Nokia N78 with this cheerful theme.

To install and change the theme on your Nokia N78, follow these quick instructions:

1. Download the file HappyFeet_n78.sis to your PC or Mac by clicking on the link below
2. Then use the supplied USB cable or set up a Bluetooth connection to transfer the theme file across to your Nokia N78 handset
3. You will them be prompted that a new theme has been received. Click on Install to install the theme
4. If you want to change the theme back simply go to the main menu, click on Settings then Themes then choose the theme you want to change to

Download the Happy Feet theme for the Nokia N78 (755KB)

If you are faced with the error message 'Expired Ceritificate!' when attempting to install the new theme, follow the instructions here on how to fix expired certificate errors on the Nokia N78.

Other Nokia N78 articles:
Nokia N78 review
Connect your Nokia N78 to a wireless network
Plan a route using Maps on the Nokia N78

When installing some themes or software to your Nokia N78, you'll see the dramatic message "Expired certificate!". This is because security measures within the Series 60 operating system only let you install themes which are less than six months old.

But all is not lost, and that great theme can be yours after all. You just have to move the date on your N78 back a year, install the theme, then change the date back to normal.

To change the date on your Nokia N78, follow these instructions:

• Click on the Menu button, highlight Tools and click the centre selection key (the 'OK' key)
• Highlight Settings and click the OK key     
• Highlight General and click the OK key     
• Highlight Date and time and click the OK key
• Highlight the date and click the OK key
• Use the Right navigation key to highlight the year. To change the year back one year, press the Down navigation key once
• Press the red End key to return to standby mode.

Now install your new theme. If you still see the Expired certificate error, change the year back another year and try installing again.

When it's installed, follow the instructions again, setting the year back to the present by highlighting the year and pressing the Up navigation key once.