Knowing

If you want to backup your e-mail from your Gmail account onto your computer its very simple.
Just use Mozilla Thunderbird or Outlook Express and follow the below steps - 

1. Sign in to Gmail.

2.Click the gear icon in the upper right, then select Settings. 

2. Click on Forwarding and POP/IMAP.

3. Select Enable POP for all mail or Enable POP for mail that arrives from now on.

    Make sure the setting is set to "Keep Google Mails copy in the inbox". 

    Also if you look on that screen there is also a link to Configuration Instructions, if you click on that link it  will take you to a page that shows you how to set up your e-mail program, like Thunderbird, or Outlook Express.

4. Now click on Save Changes

For ease I would highly recommend using Thunderbird rather than Outlook as Thunderbird has all the Gmail servers already built in to it.

For Thunderbird 

1. Open Mozilla Thunderbird 

2. Just go to the "Tools" menu and click "Account Settings".
3. In the Account Settings box click on "Add Account".
4. Select Gmail from the list and click Next
5. Enter Your Name and Gmail address
6. Click Next and then click Finish.

All the other settings will be automatically set up for you.

When you click on the Get Mail icon in Thunderbird it will then ask you for your Gmail account. If this computer is only going to be used by you (and anyone else that you dont mind reading your e-mail) tick the box "remember password" and then you dont need to enter your password again.

It will then contact Gmail and download all your e-mail to your computer. Here you get all your e-mails in your computer.