Airport Express cannot connect to 5ghz network?

I select "Join or extend Wireless network", select the 5 ghz SSID, and it just never connects, it gives an error message about being unable to join - I just tried again via the airport utility going into the wireless settings and switching the SSID and hitting update and then it loses it's connection, flashing orange now..then finally an error message "An error occured while updating the configuration" only way I can get it back now is to hook up via Ethernet..

I've completely reset it now and on my windows PC, and I don't even see the 5GHz network on the list..but I see the 2.4 GHz..how is this possible if my Macbook I'm on right now is on the 5GHz and I've verified via hitting the control key and looking at the network?

WOW so after all that it turns out somehow in memory even after a factory reset it was looking for my original SSID which was on dual 2.4 and 5 ghz when I first set it up..after some more troubleshooting I hooked it up to my PC with factory settings and couldn't even find the 5 ghz SSID..after that I disabled the 2.4 ghz SSID completely from the router and then I couldn't see anything..after more troubleshooting I renamed the SSID name to something new and now the airport connected to the 5 ghz, re-enabled the 2.4 with a new name and everything is working great! Thank goodness!