How do I check my window regulator on my car?

[Michael]

I have an 03 Rendevous that has a window (driver side front) that doesn't work. I have been trying to diagnose the problem...One of them was the guides which I changed properly because the old parts were broken. This did not completely fix the window. Someone suggested in a previous question it's a window regulator problem. How do I check the regulator? I prefer to do this job myself as I am a sharp car guy. Serious answers well appreciated. Thanks