Just a wild guess here but is your router updated with the latest firmware? This fixed many a SL2 issue at SBS as a lot of routers out of the box have bugs in the security software which have been addressed in updates.
We got him working via USB refresh. For some reason we are still working with him, the wifi router and the G2 are not communicating with each other properly.
Honestly, we haven't had other issues like this one, so we are still troubleshooting on this particular issue.
Honestly, Wifi almost always works out of the box with no issues. The issues that people do run into are normally associated with older firmware that didn't handle spaces in the network name, or people typing in the password in caps rather than lower case.