Every few year we tend to change computer, the hardware can’t cope with modern demands, so that machine usually end up gathering dust somewhere in a cupboard in case the new one get defective or that we don’t know what to do with it. Sending it to the recycler is a good idea or course, its way better than in a landfill.
However, there may be some use to it, especially if you where planning to get a NAS to share file or printers across computers in you home network or when you are away from home.
Of course, you could buy a NAS; they are relatively cheap, but why buy when you have a working old computer at home and can get free open-source software to do the same thing.
What I recommend is Amahi Home Server (http://www.amahi.org/). It will transform that old computer in an easy to use server that will enable you to share disk space across computer securely and it will be able to provide others service when your not home like music streaming, vpn, etc.
The VPN apps could be very interesting if you frequently your device over open wifi network in public places where you are susceptible to be spied on by any hacker on the same network. With a VPN connexion to you home, I’ll the surfing and transaction will be encrypted securely becoming virtually undecipherable by would be snoopers, making you surfing safe anywhere you are.
It does not require a very powerful, the minimum requirement is: 1GHz CPU, 4GB Disk, and 512MB RAM. A 10-year-old desktop could do this. You could attach all these USB hard drive you have and centralize the storage and manage who can see what. It is also practical when you forgot a file at home; you can login to your server from anywhere and get that file where you are now.
You can even manage it remotely, so you do not event need a screen and keyboard attached to it, so it can be stored out of the view.
There is so much apps available for this server that I am sure you’ll find a use for this old box sitting there picking dust.