Simcard not recognized

[Goldenlotus]

My new Xperia J (a month old) is suddenly not recognizing the sim card, I tried with an alternative one, but the problem persists. If I restart it works for a min and then there is no signal. I tried to resetting the phone to factory settings - it worked for a few hrs but again the same problem. How can this be resolved quickly.

Thanks

[Samuel1]

I'd recommend that you try to repair the software via PC Companion. Download and install PCC from there:

http://www.sonymobile.com/update

If the problems still persist after the update, you should send in the phone to a service center for repair.