Sometimes when installing themes to your Nokia N73, you might have come across the dramatic message "Expired certificate!". And you won't be able to install the theme.

This is because security measures within the Nokia 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 N95 back a year, install the theme, then change the date back to normal.

To change the date on your Nokia N73, 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.