Oops, I'm very dumb. Both wireless adapters are internal, and I didn't know that they had to be turned on with a super secret On button. Sad

But the good news is that not only is the connection up and running, but the whole file sharing thing works like a charm! Happy

So thank you all for your silent thoughts and prayers that got me through this rather stresslessly - I'm certainly a much smarter man for all the reading I've done, and I hereby proclaim myself Apprentice of Ad Hoc Networking (level 20). Ok, less gin and more bed...