Why does the passenger side window make a.

Why does the passenger side window make a squeaking sound when closing it?
I bought my car earlier this march and the passenger window was working fine. Than a few months later whenever I tried closing the window, it would make a squeaking sound as if it was having a tough time pulling it up. I never thought much of it until now. Just yesterday I left it open a crack while I let the car warm up. Im terrified of leaving the windows closed while my car is running, for fear of it locking on me (past experience) So when I was about to leave, I tried closing it. Again, the squeaking noise. Except this time it stopped halfway and wouldnt budge. I kept pushing the button and it would go up an inch but than it would go down again and stop halfway. I pushed the button a few more times and every time, the window would go up. But than stop. So it took a while but I eventually got it to close. I havent opened the window since just in case it wont close again. But I don't know whats causing the problem. The window regulator? The power window? Im not sure.