Can't get teamspeak to recognize microphone

I am trying to set up teamspeak on behalf of a friend. Teamspeak continues to display the "microphone disabled" icon. We cannot re-enable it.

We have tried:

-Different types of voice activation; push-to-talk, continuous, and voice-activated.
-All the options for capture device.
-Connecting and disconnecting several times and restarting the computer
-Running Teamspeak as an administrator
-It's a brand-new install, so there are no capture or playback profile set in the bookmark
-We checked and double-checked playback and capture devices in Windows
-Teamviewing the computer
-Changing his permissions on the server. The server is up and works for everyone else.
-Trying a different server
-Notably, we can hear his microphone in teamspeak on the microphone test, but we can't get the microphone to enable

We have tried both versions 3.17 and 3.18. He is running Windows 8.1. Microphone is whatever microphone is in a Polaroid PHB 8500 headset. The drivers were updated to the latest using the Windows driver update wizard. Computer is a Gateway Z5WTC

Can't get teamspeak to recognize microphone