I forgot the unlock code to switch on the phone...

I forgot the unlock code to switch on the phone...

My screen got damaged and had the phone given to a friend's shop to have it repaired.But due to lack of availability of the part,it had laid unrepaired for quite sometime.In the meanwhile i bought a new phone and i gorgot the old code to even switch on the phone that i has been repaired and delivered today.plz help!!