i am having problem with my net in my xperia play since today afternoon.
i don't know wwhat's wrong i tried switching off and on. i can make calls and send text.
EDITED as mis read.
Making calls and sending texts does not need any settings, but accessing the internet does.
Check that you have not had O2 work in your area here: http://status.o2.co.uk/
If nothing showing try a soft reset by turning off your phone and removing the battery.
Leave for 10 mins and replace.
If still a problem go to your applications list and find task manager.
Close active applications
In RAM Clear Memory
Now try again.
If still a problem you may have to consider a factory rest, but you will lose data and applications, but not contacts.