If you are running Windows XP you will need to install the Windows easy transfer files to your external hard drive first. Hit next at the first window, then hit An External Hard Disk or USB Flash Drive. Then click this is my new computer and hit "No" at the next screen. Click I Need to Install It Now and pick your external hard disk when prompted. Windows will copy the necessary files, which should only take a minute.When it's done, unplug it and plug it into your old computer. If you don't get an autorun prompt, head to My Computer and double-click on your external hard drive. From there, it'll ask you if you want to install Windows Easy Transfer on your Windows XP machine. After it does, it will scan your computer for data to transfer.