I've worked and lived in several African countries for almost ten years now.
Africa is a big place. I live in Uganda and our situation is quite different from what you describe.
There is no shortage of old computer parts, they are shipped in by the cargo container.
Not here. We have no import duty on complete units while parts and accessories are heavily taxed. Furthermore, nobody is sneaking in containers filled with useless garbage. Pro-ban advocates in Uganda (and other places) commonly use emotional rallying cries like "We refuse to be the dumping ground for the rest of the world!" International dumping may be an issue for coastal countries, but nobody in their right mind is going to /pay/ to ship something (especially valuable materials) to Mombasa then /pay more/ to truck it overland through Kenya just to dump it on an inland country like Uganda.
I am well aware of charities out there who like to package up used computers and sent them off to Africa, the truth is, the computers are old and mostly useless.
Hardly. Prior to the Finance Amendment Bill of 2009 which banned /all/ second-hand imports, the most commonly imported units were Pentium 4s with 512MB RAM, a 40GB HD, keyboard, monitor, and mouse. That's more than enough power to run a modern OS, Photoshop/Gimp, AutoCAD, office software, and a web browser.
It's actually much cheaper just to source a brand new dell laptop from a local supplier than to ship in in from half way around the world.
Prior to the ban, a working second-hand computer (as described above) cost $100 from retailers selling /at a profit/. It's now two years since the ban took effect and the cheapest new computer (desktop/laptop/netbook) costs $300. Essentially, computers are now far less affordable than they already were.
but realistically, setting up a refurbished CPU, monitor, keyboard, powersupply, stabilizer, ect... it takes a lot of work. It also takes maintenance and training. It takes a lot of money to do all this.
So we should increase costs further by by eliminating a source of inexpensive computers? Just so you know, many organizations which were building school labs and training thousands of teachers in Uganda (like Camara) were funded by profits from second-hand sales. Since the ban, they've halted these operations and/or left the country.
I'm rambling now, but back to the e-waste, it's a huge problem, but on the other hand, if someone were to set up a properly functioning e-waste recycling business and properly employ the young men, give them training, and safety equipment, they could do a lot better for themselves.
Here's a fun story: An organization in Uganda (Second Life) had been promised land by the government to set up a commercial e-waste recycling facility. When the Finance ministry decided to ban second-hand imports (see above) they also wrongly assumed they had solved the e-waste problem and took the recycling facility land back. Here's a quote by Dr. Aryamanya, Director of Uganda's National Environment Management Authority, on why the government decided to pull out of the project (source):
it would encourage the continuous importation of second hand computers and other electronic waste and would therefore negate the objectives of the ban.
Who the hell gave this guy a PHD? Tell me, doc, what are we going to do with all of our new and used electronic devices when they reach end-of-life? Have witch-doctors banish them to another dimension?