I have a 1999 Audi A6 and a couple of days back the driver side window glass started malfunctioning, when I slide it down, it refuse to come up even if I tries continuosly. looks as if something is dragging it downwards. It tries to come up and then slides back down. The back window at the driver's side now also started copying it. Is this a problem with some loose wire or something else.
This behaviour is only at the driver's side front and rear windows. Please suggest what could be the problem.

 

it sounds like the window regulators... probably more specifically the plastic guides are broken.

you may want to check out the following articles, although only one is for A6
(the procedure should be somewhat similar for all the models, despite maybe a different design in taking apart the door panel) :

--- Window Regulator Replacement - A4, S4

--- Window Plastic Guides Replacement - A6