Open Mozilla Thunderbird, select Tools and from the drop down list select Account Settings

Within the Account Setting screen click the Add Account… button, this will immediately display the Account Setup Wizard.

Check the option Email Account and click Next to continue.

Within the Identity window enter in your name in the Your Name field. Within the Email address field enter your NewNet email address that you created within the PowerHost control panel and click Next to proceed to the next window.

Within the Server Information window make sure that the POP radio button is selected.
Enter your virtual mail server settings in the Incoming Server box. The part of the mail server address is the username that you chose when originally signing up for NewNet Broadband and click Next to continue.

Within the User Names window please enter your Incoming User Name which is the email address you set up within the PowerHost control panel and click Next to continue.

Enter an Account Name for your email. The account name can be anything you like as it is just a reference name for the email account to make it easily identifiable for the future and click Next to continue.

The Congratulations window displays a final overview of your new email account settings and you should check through these settings to ensure they have been typed in correctly. Click Finish once you are satisfied with your settings.

Once your email account has been set-up you should now try to send and email.
The first time you try to "Send & Receive" email you will be asked for your password. Make sure you enter this correctly and tick the box to make Thunderbird remember your password.

If your email account has been set-up correctly then you should be able to send and receive email.