Driver door panel and window removal

front or rear
is it electric window or manual?
your question is missing alot of info..

manual window handle has a retaining pin which needs to be removed and bolts all round the door

Remove the inner door panel to see the issue

Most likely a broken window regulator,has to be
replaced

Could be a bad switch,you have to be more discriptive

Chances are it's the door mech that's gone it needs to be broken from the inside any dealer or specialize garage should be able to do this

sounds like the hard wire attached to the key lock may be off or broken..this happens a lot when a car is "slim jimmed" or used a coat hanger to unlock the door.. or it could be from just normal wear.. the door panel will have to come off the door to be able to look inside and see what is happening.. simple, inexpensive fix for someone with a little mechanical ability

Replace the switch. It has lost connection to the up position.

Check wire harness between driver door and body for broken wires.Wire harness bends , when door opens and closes so it may brake the wire or two inside harness.

On the inside trim, you can remove screws that are by the door handle, arm rest, under door and side of door and then gently pull back on the panel as there will also be retaining clips attached and you don't want to break them. You'll need to lift the door panel upwards in order to get it off the window ledge. Then you'll need to manipulate the panel and disconnect the door handle linkage from the door handle and disconnect the wiring for your controls and mirror. Then you can remove the bolts securing the mirror to the door

No Manual BUT I can tell you that All Door Pannels are attached By A Combo of SNAP Fasteners And Hidden Screws, Most Parts Stores Have the Tool Cor Pannel Removal"SNAPS" And If you LOOK VeryHard the Screws Can Be Found Some are Covered By Small Plastic Covers Witch a Flathead Screwdriver will Remove.
I Hope this Helps You

roll down the window. and take the interior panel off. on the inside of the door at the morror there is a plastick cover that clips out(remove it) there is foam on the iside remove that aswell. you sould see a bolt or a skrew once loose the mirror will come out. while loosening it hold the mirror in your free hand they some times just fall off.

This is a common problem with the C5 A6 models. Before you replace the fuse for the windows (I think it's number 14, but i don't have a manual in front of me - Anyway, it's the 10A fuse that's blown!) Look under the back of both front seats and you'll see a light that illuminates the floor for the back seats. Rem ove the light from each seat by prying it out with a flat screwdriver and disconnect both leads. Replace the fuse, and your windows (moon roof and interior lights as well) should now work. The lumbar support causes something to short out the lights. I've tried insulating the lights on mine, but the problem always comes back so I just disconnected them altogether.