Ubuntu is one of the most recent and popular versions of Linux, whose design motto is 'Linux For Humans'. This operating system is very flexible in terms of media through which it can be installed on a computer. Installing it from a USB drive eliminates the need for burning installation CDs. This way, it can also be installed on netbooks, that do not have optical drives. The method of installation described below works for Kubuntu, Edubuntu, and Xubuntu as well.
Ubuntu Installation Guide
I assume in this article, that you have a pre-installed Windows XP, Windows Vista, or Windows 7 version on your computer, and you want to install and boot Ubuntu from a USB drive. The latest installation CD of this operating system has a USB bootable disc creation tool. So if you have a machine with a CD drive, you can use the installation CD based tool to prepare a bootable drive.
I explain the simplest installation method here (based on Windows), that will get your job done in a matter of minutes. Let me present the outline of the procedure. First, you need to prepare the flash drive, by copying the ISO image to the drive and then reboot the computer from the flash drive to run the installation.
You will need the Ubuntu Live CD or an ISO image of the latest version. Check that your computer satisfies the basic Ubuntu system requirements. Another obvious necessity is a USB flash drive, with at least 1 GB storage capacity. You will need to download two software programs. One is '7-Zip', which is a free compression program available online. It can handle most types of compressed files. Another program that you'll need is Syslinux, which is a bootloader that will make the USB flash drive bootable.
Format USB Drive
Insert the drive in the appropriate port on your running Windows system. Right click on the USB drive icon in 'My Computer' and select the 'Format' option. Make sure that you select the file system to be FAT32 and not NTFS. This is essential as the installation does not work with NTFS formatting.
Install 7-Zip and Syslinux
Install the latest version of the 7-Zip program. Using it, you need to first extract Syslinux from its compressed form. To do that, right click on the downloaded file and choose the extraction option to extract the file to the desktop. Rename the extracted file folder as 'syslinux'.
Now, you need to open the 'Windows Command Prompt' program and type 'cd Desktop/syslinux/win32'. To install syslinux, type in the following command: syslinux - ma [USB Drive Name]:
Create a Bootable USB Drive
Next, locate the ISO image of Ubuntu and right click on it to extract it to your hard drive. Simply copy and paste the extracted folder of the ISO image to the formatted USB drive. Copy all the files from the isolinux folder directly to the USB drive folder. That is, if the drive name is H, then transfer all files from H:\isolinux to H:\. With that, your job is done, your bootable USB is ready.
To boot from USB, restart the computer and set the bootable drive to be the USB drive. To do this, you will have to press F12 and change the boot options through the BIOS screen. Once this is done, you can install the operating system from the flash drive to the hard drive or use it to boot into Ubuntu directly.
There is a program called Unetbootin, that has been specifically designed to create bootable USB drives. You could alternatively download that program and create your bootable flash drive directly.