One of the upvc windows in my house would not open so I unscrewed the handle off to have a look to see if i could get the window open. I have found out from looking at the working windows in my house what the problem is. The bar what come out the handle is square and it fits in the square mechanism in the window just like a normal interior door. What has happened is the mechanism on the door has gone round so when the square bar is going in it is not getting a bite. I have tried a screw driver to see if I could maybe wedge it in as once open I can unscrew the mechanism and buy a new one but I got no joy. Anyone got any ideas how I could possibly get this open?