How to change the os of my nokia 5310 ? - Nokia 5310 Cellular Phone

Update using your phone You can download most software updates straight to your phone, with no need for a PC.
These free software updates from Nokia keep your phone working at its best, with improvements to battery life and performance as well as new features.

1. Select Menu > Settings > Phone > Phone Updates.
2. Select any available updates you want to install.
3. To download, follow the on-screen instructions.

If the software update doesn't appear, learn how to update your phone's software by consulting your user guide
Update using your PC If you use a PC, Nokia Ovi Suite can check your phone's current software version and download new versions when they become available, using your PC's internet connection.
Nokia Ovi Suite also helps you to back up your contacts and photos, synchronise your calendar and update other applications such as Maps.
To update your phone's software using Nokia Ovi Suite on your PC:

1. On your PC, open Nokia Ovi Suite and connect your phone
2. In Nokia Ovi Suite, select Tools > Software updates.
3. From the list of available updates, choose what you'd like to install.

It's free to download and use Nokia Ovi Suite. It runs on Windows 7, Windows Vista and Windows XP.
Note: If you're a Mac user, you need to update your software from your device as Nokia Ovi Suite is not available for Mac OS.