I was having an issue with my left front window (US driver side) shaking about half way through closing and my rear right window squeaking when opening and closing.

I did a little research here and on Google and can report that within 5 minutes and without spending more than a few dollars I fixed both problems.

All I did was go to Home Depot and get a can of "B'Laster Silicone Spray Lubricant" which cost me $3.47. I then carefully sprayed it into the side tracks of both windows (making sure not to spray it all over the car), rolled them up and down a few times, and both were back to normal!

I also used this stuff on my sunroof which was starting to creak a little when tilting up and it fixed that too!

Hopefully this helps others with the same issue.