Sometime back the driver side window had stopped working. I could not roll it up. So I had to get the window regulator changed for that window. But after the change, now I can roll it up again, but its not smooth. In the beginning, it was only slow when rolling it up. But with time its becomming harder to roll it up. The windows rolls up fine till half way through but after that it looks like something is pulling it back and its very slow to move. Sometimes I even use my hands to help the window move up.

Can someone please tell what could be going wrong.

Thanks