Nokia 5700
Keys are not working

My nokia 5700 xpress music phone's keys are not working.

i dont know why.

please tell me.what has happened to my phone.

and earlier also i had nokia 5200...

but that time it got water damaged.

is it true that...

water damaged cell can not be repaired..???

but my nokia 5700 is not water damaged... but still its keys are not working..

plzz help me..

as early as you can.plzz..

i request..