Wi.Fi problem

[FinallyFoundYou]

A few days ago came into my 'safe mode'. I reboot the phone and applications that have been deleted, appeared. But Wi-Fi does not work. Turn it on and poslije few seconds it turns off and can not find any device. I do not have cable, just a phone. Does anyone know what I should do?
P.S sorry with my bad english

[Alexander1]

Can you find any other routers on other locations? Does Wi-Fi works in safe mode?

http://talk.sonymobile.com/t5/FAQ/How-to-boot-your-phone-into-safe-mode/m-p/348008#U348008

If you can't get Wi-Fi to work at all I suggest that you repair the phone software using PC Companion: 

http://www.sonymobile.com/update

In PC Companion, press start on Support Zone > Start on Update the phones software > Press the blue link that says "Repair phone".