1) Download the lubuntu .iso from http://lubuntu.net/. Choose 'x86 CD' if you have an older computer, and 64-bit only if you have a newer computer with 4gigs of RAM or more.
2) When its downloaded, right click on the .iso file, and chose to burn it to disc. If there is no option to do this, search for 'iso burning windows XP'
3) Leave the disc in after burning, and restart your machine. To boot from the disc, there is normally a key combination you'll need to do (like hold the 'escape' button). Again, you can search for this dependent on your computer.
4) Follow installation instructions and you're away. You'll find it amazingly fast compared to XP
Best is to Use IMAP if you insist on POP se the alternative at the bottom.
Since you are using the POP protocol in your mail client. Mails are most probably being downloaded to your email client and removed form the server
(check your email client settings to verify this)
If you were running IMAP already you would only need to to Step NR 3
1) Set up IMAP on your old mail client.
Disable checking of email with the POP account but do not remove it
and re add another the same email account in your windows email client, but this time with IMAP support instead of POP support.
Since IMAP will not download and remove emails from the mail server ,but simply make an cached version of your emails in your email client. Allowing you to read delete and otherwise interact with your emails from multiple devies.
2) Move emails back to server
Once that is done , drag and drop all your emails from your pop3 inbox in your mail client into the IMAP inbox you should be having.
This will basically re-upload the emails onto your e-mail providers server.
3) Configure IMAP on thunderbird.
Once all email have been moved back.
You can simply configure your thunderbird on linux or any email client
to gain access to your emails.
In general IMAP is always preferred over POP as it has better support for handling email when using multiple email clients in multiple locations.
If you insist on continuing using POP:
Since the Thunderbird file format is the same between different operating systems you can actually extract the data file manually from the install folders.
But it might be easier just to install the import export add on ,
export the emails with it , move that file to the new place and import it with the same add on.
Best Answer
Seeing the hardware you have (CPU: 1.6 GHz, RAM: 1 GB) I recommend to download Xubuntu or Lubuntu before testing Ubuntu. This is not related to which one is better but I am trying to make sure that the Ubuntu version works OK on your hardware. I also would recommend, like Devesh said, to wait until 14.04 is out (Which will happen next week on April 17, so the wait won't be long).
Here's what each of them would look like once you have them installed:
Lubuntu
Very lightweight Desktop environment (Lightweight meaning that it uses small amounts of RAM, CPU and HDD space). The menu, where all the apps can be found, is located in the same place as you have them in Windows XP.
Xubuntu
Another lightweight Desktop environment. The menu can be found in the top left corner so instead of going down to the bottom right corner, you would go up.
Ubuntu
This is the main Ubuntu distribution. It uses a bit more resources than the other two, but I have tried Ubuntu on computers with 512 MB of RAM and it has ran correctly. You would also need a good video card. Still, you would need to personally test this. From Booting time, to how fast apps opened, to how fast you can work and be productive with each Desktop environment.
You need to know that, independent of what Ubuntu flavor you decide to select, you can install from any of them, the other desktops to try out. What I mean with this is that, if you download Lubuntu, Xubuntu, Ubuntu, Kubuntu, Gnome Ubuntu or any Ubuntu official version, you can install from the Software Center (The application that manages installation of other apps and updates) any other Desktop environment. So you could have installed Xubuntu but you also wanted to try out Lubuntu, so you would go to the Software Center and download the
lubuntu-desktoppackage. This would make your system have both, Xubuntu and Lubuntu. you can choose which one you want to use from the Login Screen.I would also invite you to read about Start Ubuntu which guides new Ubuntu users into this open source world.
So with everything here said and taking your hardware into consideration my recommendations would be:
lubuntu-desktopfor Lubuntu,xubuntu-desktopfor Xubuntu...)So with all of this said, I applaud you and say: Welcome to Ubuntu my friend.