First off, if it's really, really old, you might need to recycle it.
if it has at least 256MB or 512MB of RAM (or could have, if you bought
more memory), there are a number of things you could do with it.
- Use it in front of the TV or in your kitchen. Install Linux on it.
It will cost you nothing to try. You burn a Linux image onto a USB
drive or a CD, put it in your old computer and install. You then have a
working system. While it may not be fast, I bet it would still be good
to look up recipes in the kitchen or movie actors in front of the tv.
We have an old laptop that regularly overheats and has to be plugged in
sitting on the coffee table in front of the TV just to answer random
questions. (Or take a quick peak at email or Facebook.)
- Donate it. There are lots of places that will take a computer with enough working memory. Kids on Computers is one. Your local school system might be another. Your local user linux group may know of others.
- Give it to a kid. My 9 year old has a hand me down computer. As
long as it runs some kind of flash player and can surf to lego.com,
What else would you do with an old computer?