If you are going to be donating an old computer to someone, it is a good idea to erase the information that is on the hard drive. If you have had the computer for several years, it is easy to forget what you have on the hard drive and ther might be some personal information that you would not want to pass along. There are many ways to attempt to remove information from a hard drive, if you search Google for free programs that profess to do this, you might get lucky and find one that does a pretty good job. You can also purchase programs that profess to do a complete job, but you really don't know if they do or not. In my opinion the only safe and sure way of protecting yourself, is to completely destroy the old hard drive. I am sure that the places that accept old donated computers, also have hard drives laying around that can replace yours. So if it were me and I was giving the computer to someone I do not know, I would remove the hard drive and take a hammer to it, then donate the computer.