This is becuase when set up the stop also sets a minimum spring power.
Do not pull out the crown unless yo want to set the watch.
One way to get a good idea whether it is there is to let the watch run down and wind it one "click".
If it has a Geneva stop, and it is set up correctly the watch will start on the first "Click", without being jiggled.
Chris Ozdoba has also written up a good explanation of how to open a watch case. This is probably the most common question watch collectors have.Sometimes it is easy to answer, and sometimes it is impossible.Some companies (as with the Gruen Watch Company), even lost rocords to fire or other natural disaster. I am sure they had no idea that their timepieces would someday be collected.
There are several ways to get an idea of when your watch was made.So to determine when your watch was manufactured, you will need to find where your serial number fits within the range of numbers.