How do I turn off Function lock on laptop

[rug]

sorry for the noobness but can anyone tell me how to turn on the fn function lock on a sony vaio laptop.

 

[rug]

My mates turned on it from the keyboard and now certain keys are now the smaller "function shifted" characters. There must be a way to cancel it from the keyboard I guess?

 

[rug]

could be , I havent got the laptop here, mate called me this morning for help.