Those old computers find their way to landfills, their rare metals and toxic components left for another generation to deal with. The local government will normally deal with it for free, as long as you set the problem out by the road on trash collection day. But that doesn't mean the problem goes away. It also doesn't mean that the resources used to create those materials couldn't be reused or that they needed to exist in the first place. Recycling is an obvious solution to some of the waste.
Many large companies recycle their office paper, for example.
But that's not always possible in some communities. Perhaps a better answer is not to use the paper in the first place. For example, I routinely receive press materials from agencies who start by sending an e-mail to announce a product. Then they send me a fax. A few days later, I get the same documents in a sturdy cardboard FedEx envelope.