Unfortunately I'm painfully aware of just how little my son knows about security, we've had too many conversations about it leading up to this. That's precisely why I decided the best option was to exclude his machine from my network. He has gotten better, and now runs an antivirus and a firewall. But he only came to that after his computer slowed to the point of almost stopping. I'm washing my hands of it and moving on.
Fordem, thank you for the sterling advice. So simple I should have thought of it myself - but I didn't. After playing around with attempting completely unsecure, open connections, I took the matter to D-Link, who decided I have a bad DIR-615. It appeared to me that it couldn't seem to dish out an IP address, but I can't confirm that.
The unit is being shipped back to D-Link, I should have a replacement in a week or two. I'll post back then.
Thanks again...