window problem

hi everyone,
i own a 2004 renault laguna 1.8 16v expression.
i was on holiday in march when i had to open my drivers window to show a pass on the security gate,my window judderd a bit,went down,started to come up again but stopped about 2 or 3 inches from the top and never went any further.it went down again but stopped at the same place when i put it up. and there it has been ever since.
has anyone got any ideas on what it could be?
thank you in advance.
paul.

I had the same problem recently, which was diagnosed as the 'window regulator'.
This is a set of pulleys/cable which controls the window motion.
The motor itself was OK, but the cables had become frayed and had consequently jammed.
It cost me about £300 for my local garage to fix it!