Can you get new locks fitted on a window that is 18 years old?

Just moved house a couple of months ago.
Now discovered that the lock is broke on one of our double glazed windows. When we try the key in the lock it won't turn atall. The problem is the the double glazing was installed in 1992, 18 years ago. So the guarantee is out of date and the company that installed it doesn't exist any more. Trying to avoid having to have a new window installed.