If you bought your computer after 2010, there’s most likely no reason to throw it out. By just installing an up-to-date Linux operating system you can keep using it for years to come.
Installing an operating system may sound difficult, but you don’t have to do it alone. With any luck, there are people in your area ready to help!
If it’s on a 64bit architecture, it probably can still run Linux Mint somewhat smoothly. If it’s 32bit though, best you can do is probably make it a homeserver with archlinux32 or some other silly hack.