It would be best to use WPA/WPA2 encryption instead of WEP even if it means buying a new router. WEP is so insecure now it is like having no security at all. The GUI WIFI config tool does not work with WEP. Instead you will have to manually edit the wpa_supplicant file. Somewhere here there is info...

I recently bought a RPI 3 model B. After a successful installation of the Raspbian, I tried to connect to my own WiFi. Unfortunately, I couldn't. After clicking on the SSID of my network, there popped up a small box where I could put in my network password. So, did I, but after clicking on OK, nothi...