Crank handle does not turn

It sounds like you may need an entirely new window operator. To determine which you need, can you unlock the window, manually push it open, and then show us pictures of the link arm(s) that push and pull the window closed? That will help narrow down what you need. 

If it doesn't open by pushing it, and the locks are undamaged, then there may be a problem with the hinge set, or the operator arms are rusted. In that case unfortunately, your only bet may be to hire a professional to help you get the window open. Apologies for any inconvenience.