Broken computer gear can be sometimes fixed. I know two main sources of problems, bad capacitors (mostly the big electrolytic ones) and solder balls breakage on cms chip (typically the chipsets that reach crazy temps on use). I fixed once a 1gb/s D-link Ethernet hub that way, some caps were notably bigger than usual, i found some spares on an old broken mainboard. Quite a shame theses pieces or hardware are made with low quality componants ! The hub was just a few years old when it had the fault.
The second kind of problems leads me every 8 month or so to put the graphic card of my laptop in the oven at 250°C during 15 minutes, just to fix the solder balls because with the thermal stress and the low quality of the solder (some lead free stuff i presume), the graphic card develops after a few years some artifacts. This can happens not just with GPU, and you will find a lot of forum threads on the net about this way of fixing (try "oven+gpu" on google).
As for reselling, look on ebay to have an idea of your gear. As far as i am concerned i have given a computer to my relatives, it was a shiny and powerfull dual cpu AMD Athlon computer at its time, but is not so by today's standards. It's however perfect for googling and emails. But unfortunatly people tend to even refuse theses old computers, even if they can be usefull, because of the size and it's way too creepy when everybody has a little pimpy smartphone or ipad. You don't want to show to your friends that old noisy beige box.
People that would be happy with them are probably in Africa and various moderatly developped countries, but the gear would be somehow expensive to ship and not sure the guys there would have the electricity.