What do I need to do before I donate my old computer?

You should wipe the computer if it has sensitive information on it. If there is no information that could be used to harm you, then let them worry about wiping it.

I say nuke the hard drive. the program I’m linking to is intended to permanently wipe data from a hard drive.
http://www.majorgeeks.com/Dariks_Boot_and_Nuke_d4596.html

Erasing the hard drive is surely the best thing to do, even if you consider any information on it to be harmless to your privacy. Drives can be undeleted and bring out any files ever downloaded or saved on them.

Next, think about the extra’s you’ve added over the years, is there any card or feature in or on your computer you would have a hard time replacing.

The computer has Windows 95. I’ve decided to reformat the disk 8 times, but I understand that I need a disk to do it. The only disk I still have around is the original boot up disk. Do you think I can use that to wipe out the C and D drives?

Always save all your important information and then erase the hard drive before selling the computer. If your going to sell it you might want to do a courtesy and save all necessary drivers on a cd Rom drive for the next person before erasing the hard drive, especially if it is older and some of the drivers may be harder to find.

For a 10 year old computer, most of the parts won’t be salvageable, so don’t worry about taking out most parts (the except will be memory if you’ve recently purchased new memory and know it’ll work with your new system).

However, do REMOVE the hard drive. Don’t wipe it. Destroy it instead. Even after wiping, information can be retrieved from it (though, admittedly, there’d have to be a good reason someone would need your information, as after securely erasing a disk, retrieval is difficult, but not impossible).

Ways to destroy it include blowing it up (fun!), dropping it repeatedly off a tall building (fun!), shooting it in the desert (fun!), or using a sledgehammer on it (fun!). Always wear safety glasses when doing so.

Once removed, donate the rest of the computer.