Since the email application is not opening whenever you access it, you may re-install the software of the mobile phone using Nokia Suite. If there's an update available for the software or application itself, you may also do it using the same software. Download Nokia Suite at this link and install it on your computer. Once it is installed, connect your mobile phone using a USB cable. You will see the picture of your phone on Nokia Suite once it is already recognized. Click on Tools tab on Nokia Suite and select Software Update. It will show you if there's an update avaailable for the software or application. If it says the current software is installed on your mobile device, click on re-install button to fix some issues on the mobile phone.