We got a call today from someone whose window would not close properly. It was a UPVC window and one of the hinges was damaged which is why it wouldn't shut. Everything worked fine after we changed both hinges (don't change just one as they have both been used the same amount so the other one will probably fail fairly soon). The window did not have any lock fitted, which is often a requirement that insurance companies insist upon in their policies. All the windows in the house now have locks fitted. Read more about windows.