Got an old computer? Installing ubuntu on an old PC is a great way to recycle and breath in new life to old systems. However, what if the old PC's optical drive is busted? This is even harder if you have a laptop since optical drives for laptops is harder to find and expensive. Well, no worries. As long as the computer can boot from a USB external drive (I was surprised that an old Dell laptop from 2004 can do this), you're in for a treat!
You need a running windows/linux system (can be the same system you're planning to install ubuntu to) and a USB flash drive. Download the ISO of ubuntu, and UNetbootin. Make sure there is enough space on the flash drive for the ISO. Install and run UNetbootin. Select the ISO and the target flash drive, and let it run. It will make the flash drive bootable, containing the ISO. After it finishes, reboot, go to the BIOS and set the computer to boot from a USB device, plug-in the USB flash drive (if you haven't done it), and you'll be greeted by the standard ubuntu installation. What's the treat? The install process is much faster than using a CD simply due to the faster read rate of USB flash drives. You'll be up and running in no time. Neato.