I have established USB tethering(using Samsung gt-s5303) 2days earlier. It worked fine until I restarted by laptop yesterday with the tethering enabled. Since then, my tethering is not working. I have tried to establish portable Wi-Fi hotspot and it also failed. At the worse, now I have found that even my broadband is not connecting also. Whereas all the mentioned connections are working well on my PC. Please tell me a way to get back my connections. I am using Ubuntu 12.04LTS. BTW, I have not updated any software except Firefox in between the scenario.