try turning your router on and off, turn it off wait 2 mins then turn it back on your router, restarting your computer as this clears any static build up, open CMD as a Admin, and type in ipconflig /f...
Could be a cache issue. If this is with Firestorm: Dee clean your cache. Opensim works different from SL here. For Secondlife, cleaning you cache is generally not advised. For Opensim, it's very neede...