I apologize for having to create another thread about this, but after about three hours of googling, none of the numerous threads about Wi-Fi issues seems to quite match up with my setup or symptoms.
Here's what's happening: I recently wiped and reinstalled NOOBs onto my Raspberry Pi 2 to take advantage of multiboot capabilities. Mostly I want to use Raspbian. I've got a TrendNet USB Wi-Fi dongle attached, and the other OS's (LibreElec) can use it just fine - it sees networks, connects to them, and transfers data like normal.
However, when I log into Raspbian, when I click on the Wi-Fi panel, it says "no wireless interface detected". Right clicking and trying to open network preferences gives me an error about permissions. I don't know the bash command to open up that particular panel, otherwise I'd try sudo-ing that.
The driver and firmware appear to be in place. I tried messing with various conf files with no luck. (I've since restored them to their defaults). I tried
ifdown wlan0 and
wlan0 ifup but I get a DHCP error, (no response after some time).
The most promising thing happened when I hooked it up to Ethernet, downloaded wicd-curses, and booted that up. Up popped an accurate list of available Wi-Fi networks. But it won't connect to the only one I have a password to. I'm quite sure I'm entering the correct password, and I've selected the correct encryption (WPA 1/2 passphrase) but the log file says
Any ideas what I should try next?