Share your experience!
After the update wifi doesn't work anymore, what can i do to get it working again, i have already tried repair but the problem is still these before the update it was working fine
Thanks for posting and welcome to the forum! 
Have you checked the thread on the link below, that holds a bunch of good tips when it comes to wifi issues? 
http://talk.sonymobile.com/message/154244#154244
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I have tried all these settings and still no connection, to test i have also updated a perfect working Xperia P to ICS and also this is now not able to connect to the WIFI.
We also have a Xperia S which is working FIne
If it still persists then delete the saved Wi-Fi profile, restart both router and phone and re-enter the settings again...
That's what I done for the past 3 weeks when I got this problem... XD