If it is only one window, it may be the switch. I've had this problem twice. Both times I removed the switches (easy job) and sprsyed them with contact cleaner and the problem was solved.
Also, through experience, I have learned that a fuse that looks good may still be the problem. If the metal of the fuse has turned dull through aging it may no longer be making good contact. Sand the ends lightly to return the shine and conductivity. Then reinstall. This has cured several electrical problems for me.