What to do?? Window won’t close at all.

The same happens when I try to close it against the frame. I put WD-40 all around, including top and bottom edge of the window where there are gaps and these bolts in the metal strips that move (sorry I don’t know what all the parts are called). The handle rotates around and something slips inside, I took it off and it’s not the handle itself. The square ‘rod’ is seated properly in both the handle and the socket inside the window, the slippage is somewhere in the mechanism. I have replaced locks in my doors before and it was pretty straightforward but I’m a bit puzzled by how to approach this. What to do? Do I need a joiner? A new window? (Hope not!!)