To run Ubuntu from a USB stick, the first thing you need to do is insert a USB stick with at least 2GB of free space into your PC.
The easiest way to put Ubuntu onto your stick is to use the USB installer provided at pendrivelinux.com. You’ll need to download and install and follow the instructions.
Visit this link for more appropriate tutorial. -> http://teen-geeks.blogspot.in/2013/07/how-to-make-ubuntu-live-thumbdrive.html
1) Install this software -> http://www.pendrivelinux.com/universal-usb-installer-easy-as-1-2-3/
2) Click 'Browse' and open the ISO file you downloaded.
3) Choose the USB drive and click 'Create'.
Now connect the created USB drive while you reboot. You may have to configure Boot Device Order from BIOS setup. How to do this ? Follow the below instructions.
1) While you are booting your PC or Laptop, press del key (depends on different computers. Check for yours) to enter BIOS setup.
2) Now enter advanced BIOS featured and change boot order.
Hope this helps....
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