Let me tell you how i screwed my wireless connection (I am Using ZTE modem, forgot my model number as i am outside now).
I have a PS3 and a laptop which shares my wireless connection. To play multiplayer games, i made few changes in my modem. I went to the NAT option and added a manual IP address in the DMZ option, gave the same ip address in my PS3 also. Now my connection to my PS3 is working fine. When i restarted my modem, i was not able to connect to internet from my laptop, even it did not show any wireless connections in my laptop. Where as i tried connecting to my Wi-fi using my iPhone and it worked perfectly. Then i connected my LAN cable to my laptop and it worked perfectly. Now, the only problem is that i am not able to connect to internet in my laptop using wi-fi and it does not even shows any available connections.
Someone please help !