There are a lot of small non-profits out there that would probably love to have your used computer. I do some work with a homeless outreach organization and we are always able to put a working computer to good use. Most small local non-profits would take your computer as long as it still works.

Be sure to take all your personal data off of it before you donate it. A simple way to do this is to reformat it. That will also put your computer in the best operating condition it can for it's new owners.

You could probably also get a small tax deduction for donating it. Just ask for a receipt.

It's a way to do good with your junk!