Dont through that old hard drive away, If it still works their great to use as a slave drive. (second Hard drive) You can use it to store pics, music and a back up on. Not to mention change the paging file to it and make the Primary hard drive faster. http://md4urpc.com/videos.aspxhere is a video on how to make a slave drive on your computer,

PC Repairs http://www.ustream.tv/recorded/5020589This Video is to show you how to hook up your old Hard drive to a usb port.If the old hard drive if a laptop or a desktop, works on both.I'm running windows 7, and this works great, It does work on XP an Vista,Make sure you have a 2.0 USB port.
Thanks,MD4URPC.com