Electric windows in FD LTD

[xbxd351]

Hey guys the electric windows in my FD LTD are driving me nuts. They were all working when I got the car a couple of years ago but now both the front windows get stuck on the way up and I have to help them on their way. I have sprayed silicon regularly in the felt tracks which hasn't helped so now I am going to pull out the regs and inspect them. Can anyone give me any pointers on what to look for or replace? I know this is a very common problem with all the fords from that era so I'm sure many forum members here will have faced this problem.