Terky, 99% of the time it's the little plastic slide that has broken. You'll have to drill the rivet out of yours and then rivet the bracket to the new slide and reuse the other parts. The danger is that the cables can sometimes get really wound and damaged, and sometimes one of the pulleys is cracked from that.

The full regulator units (sans motor) aren't that expensive, but again, the plastic is the piece that will eventually break (again). In either case you have to drill out the huge rivets that hold the regulator to the door, and then pop new ones in. Some have used small bolts and nylocks, but those can be hard to line up.

The best course of action is to pull the door apart far enough to look in and see how the cable and pulleys are (you'll need an inspection mirror or a small mobile phone with a good flash/camera). If that all looks okay, then order the plastic slide. If not, order the regulator.

Good luck.