Again trash or what? Older, used, donated computers show up constantly at the Goodwill Stores, etc. and such stores don'thave anything to prove they themselves didn't steal it. I can pay online for the info (supposedly) and it be legit. It's all good though. I can learn and make for certain sure that no more money of mine goes to ANY church.
You could always just throw a copy of Linux on there instead. It tends to work especially well on older computers, so that works in your favor. If the people who ultimately get the computer don't want Linux, then they'll just have to figure out how to pay for a copy of Windows themselves. But on the other end, you're at least providing people with a working computer, not just hardware and no software.