I am assuming it is a hand winder and not electrical. It sounds as though the teeth on thewinder winder mechanism is worn and there is insufficient strength in the teeth to raise the window. The only way to tell I suggest is remove the mechanism if you are able and fit one either new from dealers or 2nd hand from the breakers. It is a very fiddly job and may be better done by a local garage.
whfreeman99@yahoo.co.uk
April 2008