Advice please

Clowance

I have a payg Sony ericsson T610 which I have not used for about 6 months. It is on 02 (I think) and has about £10 credit I think.
I charged it up today and it comes up with "phone locked, enter unlock code"
Have the network done something to it? Or have some buttons been pressed by accident while its been lying on the kitchen worktop?
I am useless with mobiles, and need the advice of the far superior intellects on this forum. Apologies if its been posted before, I tried a search but couldnt find anything.

Woby_Tide

may have reset to factory defaults, or as not used for 6 months O2 sim may well have expired and something to do with that

drahcir_2

if its the same sim you were using before (ie not trying a different network) then the default code should be 0000