Ken Hough's Website
Linux as the sole operating system:
Non technical (and cautious) users might prefer to install Linux as the only operating system on a spare PC. Alternatively, plug-in caddies can be used so as to be able to swap hard drives.
Unlike Windows Vista and Windows 7, Linux does not need a particularly powerful machine or vast amounts of RAM to run sensibly quickly. An old Pentium based PC with perhaps only 512MB of RAM will be fine for most purposes. I still have an old '486 based PC which can run quite happily as a Linux 'headless' server box. It would of course struggle with some of the modern desktop managers.
Of course, if you have a 64 bit quad core based PC with a few GB of RAM (as I have), Linux can make very good use of it.
If you wish to use your main (Windows?) PC, then plug-in caddies could be used so as to be able to swap hard drives.