We have a wireless network setup which has been configured with radius/NPS by a previous colleague. This is working well for computers which are part of our domain but we are looking at using radius authentication for guest devices and are struggling to get them to connect. We have setup a guest SSID and XP devices fail to connect requesting a certificate, whilst W7 devices ask for credentials but does not work when we enter AD credentials. We have tried installing a self signed certificate manually from the server it resides on to no avail. I do not have much knowledge of NPS/Radius and certificates - has anybody tried something similar and can you offer any suggestions?