96 Jetta timing belt change- won't start

Get a service manual!

Won't turn over usually means - nothing rotates. Turns over, but won't start is what I think you are asking. If the upper toothed sprocket is not precisely synchronized with the lower one then it won't work. You probably know this. I believe the crank shaft can be rotated twice and because it is geared down with a 2:1 ratio to the distributor that you could conceivably have assembled it with the cam and crank toothed sprockets synchronized, but with the distributor 180 degrees out of phase. This may be the case if the belt broke while driving (before you replaced it). To fix -- remove distributor, rotate half a circle and replace. You really need to read a manual. The crank rotates 2x for every 1x the cam rotates. A manual will show you where to check for the three specific check points. I had the shop manul and Haynes and I am really really glad that I did not have to realign everything because my belt was still in working order when I replaced it. I couldn't find the crankshaft markings -- but usually this just means that they are right in front of me. If you want to, got to the dealer and tell one of the mechanics. Ask 'em nice and they might print up a picture of the alignment marks for you for free -- otherwise slip 'em a few bucks when the boss isn't looking. I used to wait by the parts counter to do this. Good Luck