window rolls down but not up '88 jetta
 

So I have had problems with my drivers side front window for as long as I've had my car (about three years) in that when rolling it up, I have to lift the forward edge up and back while rolling it up or it just sticks. Today, I rolled it down and when I tried to roll it back up the handle was very difficult to turn, even though I was tilting it back in the usual manner, eventually the handle slipped, and while it started turning (though still with difficulty) it did not lift the window. I had to get out of the car, place a hand on each side of the window and lift it up to close it. While I was lifting, the handle turned as though it was being rolled up normally, even though I was not touching the handle at all - in other words, raising the window turns the handle, but turning the handle does not raise the window. It still rolls down properly, and I tested to see if it could be opened by holding both sides and pushing down, it can't (thankfully).

Any ideas? Does this sound like something that could be fixed by a fairly handy amateur? Don't want to tear open my door just to find out I have to get it fixed at a shop anyway. Thanks in advance for any advice!