You can download Ubuntu from here. Burn the iso to a CD and run it in Windows.
- If a security message like this appears, click 'Continue' to proceed with the installation.
- To install Ubuntu, all you need to do is choose your username and password. Please note that you have to enter your password twice to make sure you typed it correctly.
- After choosing your password, click 'Install'. The files will be installed automatically.
- Wait until Ubuntu is installed.
- When the installation is complete, you will be prompted to restart your computer. Click 'Finish' to restart.
- After your computer restarts, choose 'Ubuntu' from the boot menu.