my windows are playing up in my 4dr E36 BMW.

Basicly when you go to put em up on the one touch button they get allmost to the top then fire back down again almost as if something has obstructed its path. Ive also noticed that when i put the window down it jolts forward slighty, thus making the window sit just out of place. Will this be the cause and if it is how do i cure this?

If not any other ideas?

http://cgi.ebay.co.uk/ws/eBayISAPI.d...MEWA:IT&ih=015
would these cure the problem? I believe this is a common problem for BMW's

Your help would be gratefully received as its starting to f@*k me off.