Probably you already did below things but just in case.
Reset your router, change the WiFi name on the router, check your router if it is not blocking new devices, check which security you use web or wpa or wpa2 ( if it is web maybe that's why it is not working anymore), firewall or virus scanner may block, check other wifi network or if you can connect to a hotspot from your phone (internet sharing), check if there is an update for the Stream.