Cant' Sync my Xobx controller with my PC

I have a wireless Xbox controller and received a wireless PC adapter but they won't sync up.

The software is installed, updated, the adapters green light is on. When I press the adapter button to initialize the sync it will flash.

When I press the Xbox controller to sync the lights will rotate around, like it would on the Xbox when it's determining what player it is, but after it finishes rotating it will flash repeatedly.

I've tried uninstalling and reinstalling the software but it's not helping.

Any ideas?