I wasn't trying to connect with wi-fi. For some reason the 3G just stopped working.
I ended up talking with customer service. I restarted it again and it still didn't work. But then the CS rep deregistered the device from my account and then re-registered it. After that, I restarted it again and the 3G turned back on right away like it always used to.
I'm so glad it's back to normal. I still don't know what caused the problem.
It seems it may have been related to my K3 being deregistered from my account but not from the device. I still don't know how that happened.
I wonder if, when they were processing the defective K3 I recently returned, they accidentally de-registered my current device, and that's what messed it up.
Curious though that it didn't start working after I added it back to my account and restarted it... only when the CS rep removed it, added it back, and then the restart.
Weird.
Thanks to all for the suggestions and advice!
