Sounds like you have a manual tranny. Couple of thoughts. One of your driveaxles may have issues. I don't think that the jetta has limited slip; therefore, if one of the driveaxles is broken, the other wheel won't have any traction. Secondly, the tranny may have suffered catastrophic damage.
Okay thanks I will take a look at those things. I once had a Honda that did the same exact thing and it ended up being some thing in the tranny's I just can't remember what. But I do t that Honda and VW are completely different
Can you turn the engine by hand when it's in gear? I bet you can. There is a shaft somewhere the is snapped or striped. clutch that is shot. The fact that you can start it in gear tells me a few things. 1 your the clutch safety switch is closed, 2 there is a disconnect between the engine and clutch. Is there an inspection plate on the bell housing? If you play hard with your car look at Half shafts and clutch shafts. The clutch switch need looking at. Brakes Fluid level? Good luck should be easy to find but expensive to fix. Good luck.