The hydraulic clutch stopped working.It won't shift.There is no pressure on the clutch whne you push it down.

The clutch is not adjustable it is fully hydraulic. That means it is self adjusting, if the clutch pedal engages high on the pedal and the clutch is hard to push you need a new clutch plate and pressure plate.

See if your hydraulic clutch needs fluid added or if it needs bleeding-if it went dry you need to bleed the system down at the slave cylinder on the bell housing.
If the hydraulics are working good, your clutch disc may be worn too bad to still work. If that is the case, you will need a new clutch disc, new pressure plate, and new clutch release bearing.

Check the hydraulic clutch operation. This is a clutch master cylinder with a reservoir on the firewall, and a clutch slave cylinder down on the bell housing of the transmission, with a steel tube running from the master to the slave cylinder. When clutch pedal is depressed, hydraulic fluid (brake fluid) is forced from the master to the slave. The slave cylinder should push out a little plunger that contacts the clutch fork lever-pushing it forward to engage the clutch.
Add brake fluid to the reservoir if needed. Watch the plunger on the slave cylinder: if it moves little, or not enough, try bleeding the slave from the bleeder valve. They are bled just like brakes. If bleeding doesn't help, your clutch master or the slave may need replacing. The master cylinder, like a brake master, has internal seals that hold hydraulic pressure, so force can be applied to the plunger on the slave cylinder.

Well, it would shift easily with engine off, because the transmission input shaft is not turning. Engine running and clutch engaging good, the input shaft would again be stationary and allow smooth shifting.
What you have to determine is if the clutch disc or pressure plate is bad (a new clutch is needed), or if the pedal hydraulic system has a malfunction. When you push the pedal down, a rod from the top of pedal pushes into the clutch master cylinder bolted to the firewall under the hood. This cylinder has a reservoir filled with brake fluid. When the rod forces fluid from the clutch master down a steel line and into the clutch slave cylinder down on the transmission bell housing, the hydraulic pressure forces a plunger from the slave cylinder to extend and push the clutch fork lever a small amount, enough to force the clutch release bearing (aka throw-out bearing) against the pressure plate. This relieves pressure on the clutch disc and input shaft becomes stationary for easy shifting.

your hydraulic clutch cylinder needs addressed, low fluid, or bad cylinder. these problem seem to surface during winter. hope this works for you

The transmission in a Volkswagen vehicle shifts gears only when there is enough hydraulic pressure. This is made possible in part by the clutch cable, because it connects the clutch pedal to the clutch master cylinder. The clutch master cylinder in turn transforms the foot pressure that is carried through the clutch cable into hydraulic pressure. If the clutch cable breaks, the clutch master cylinder will be unable to generate enough hydraulic pressure for shifting gears.

If your able to shift with the car off sitting in your driveway but not able to shift once the engine is running then you have one of several possible problems.

Problem 1) Possible clutch hydraulics problem where the hydraulics are not completely disengaging the clutch.

Problem 2) Clutch pressure plate fingers could be tired and not allowing the pressure plate to disengage the friction disc off the flywheel.

Problem 3) Not likely but depending on the abuse of the car, the synchros could be shot.

If the car has a decent amount of miles on it and is driven in the city a lot then Problem 1 and 2 are most likely the problem. So either way it's time to check some hydraulics or replace the clutch.

you may have a faulty clutch master cylinder or faulty clutch slave cylinder- leaking clutch fluid. most of the time both are replaced at the same time which should be recomended by your mechanic, the bolts to the master cylinder are very hard to get to and require the right tool.
you should be able to move car forward by selecting 1st then cranking engine till it starts, gear changes while driving are hard but not impossible. i recommend a tow truck to a local repairer.

If its a cable clutch adjust it by tighten it.If its hydraulic then the pressure plate is week change the clutch assembly

I will bet it grinds when you try to engage first or reverse. When this happened on my car, I adjusted the clutch and it improved. You need about a half inch of free play when you first touch the pedal with your foot. If you have a slave cylinder, (hydraulic clutch). You may need to bleed the system. With air in the system, you can't get enough clutch to fully disengage the trans from the motor.(Clutch and pressure plate) It's like you only pushed down half way on the pedal. If it's not hydraulic, it should be adjusted with wrenches. If clutch is fine, It could be a loose shift linkage. It would seem extra sloppy when moving shifter, It would just not go in gear, with out the grinding.Hope this helps. lbreen