Golf Cabrio won't start

My 1995 Golf Cabrio (automatic) won't start. When the ignition switch is turned, I hear clicking sounds, but the engine did not start. When I turned the switch longer, the horn starts to go off, the CD player start to turn on, and the passenger power window opens. Can someone help?
Thanks

It sounds like it might be two problems to me. I assume when you turn the switch longer you might be turning harder also. Strange electrical symptoms when turning the swith almost always mean an ignition switch (electrical part) problem. I'd look at this first as it may cure the other problem (no cranking). Secondly, if you hear the starter solenoid click, but no cranking, it's probably a bad starter. Another common problem - especially on automatics.

Thanks for your reply. Right now I'm trying to entertain any possibilities because it doesn't start, thus I may need to tow it to have it fixed. A friend suggested it could be the battery, so I gave it a jump start. During the jump start, when I turned the ignition key, the loud horn (alarm?) went off immediately. By the way, this was how it started, before the battery got weaker. Any opinion?

When you connect a jumper cable & have enough voltage the alarm might sound, turning on the ignition or unlocking the door should reset it. With the jumper cable connected does it try to start? Unfortunately automatic starters are difficult to get to & also are common to fail as they are under the exhaust manifold & get very hot.

When the jumper cable is connected and I turned the ignition key, the alarm was activated. Someone suggested unlocking the door to reset the alarm. I tried to do that by pulling the driver's side lock lever up. It didn't do anything. The alarm still went off whenever I tried to start the car. Do I have to unlock the door with another key?

What I meant was to unlock the driver's door with a key to reset the alarm after re-connecting the battery, no key in ignition required. There should be a switch in the door that deactivates the alarm when the key is turned. If that doesn't work your alarm might be one of the ones you have to do a special proceedure to reset. Try this: disconnect battery (first put up all the windows & turn off all accessories), turn key to on position in ignition switch, close all doors, re-connect battery.