buy a new window
usually by replacing window regulator.
change the window seal / gasket.
that car has issues with the windows and VW knows about it! Call your local VW dealer and ask if they will fix it for free! they would fix all of them for free awhile back regardless of the milage on the car!
you will have to replace the window regulator.
Try a silicone lubricant.
Dealer Warranty item.
You can purchase a repair car window kit that has the instructions on how to fix your crack. If you have insurance however, I would recommend getting a repair shop to fix it since it is covered on your isnurance.
get a hammer
depends on what is wrong with it you may need a new engine to fix it