Unlocking a blocked Ipad

I am trying to unlock my nieces Ipad from my PC, I dont have her icloud/itunes log in and I have updated/restored this from my PC but i keep getting the error message that the ipad is not connected to itunes. It is the same on my ipad which is working.

It is driving me mad!

I've asked my niece for her log in information but she doesn't know - she thinks I have a crystal ball - I cannot get it off 'iPad is disabled connect to iTunes' when I do I get the error 'this ipad cannot be found'