Can you wind an automatic watch from the crown?

Yes, you can wind an automatic watch from the crown. That will not hurt the movement. Actually with an older or worn watch, a few manual winds from the crown can be a big help.

 What does fully automatic mean?

Fully automatic means that the watch can’t be wound from the crown. The only watch that comes to mind is a basic Seiko auto. They have eliminated the winding pinion on the watch so that the only way to wind the watch is to wear it and have the auto do its work.  No idea why they did this, just a different idea of how to design an automatic watch.

Can you “overwind” a watch.

No, you can’t overwind a watch.  The reason that people say they have overwound a watch is that they wind it up and the watch does not run. They think that they have broken something by winding it too much. A normal person is not strong enough to break a manual wind watch by just winding it.

My watch did not start up when it was wound, is this a problem?

No, this is not a problem.  For a watch to start up from a dead stop when wound, everything must be in “perfect” condition. The watch must be perfectly clean, it must be in beat and hairspring and escapement also must be adjusted properly. A slight “twist” to get the balance wheel started is not a problem.

Is the information about power reserve that I read about on the internet correct??

The 38-40 plus hour power reserve expectations  that you read about in chat rooms or in other places on the internet is often misleading. The power reserve on an automatic watch is going to depend on the quality of the watch, is it clean and oiled properly, is the mainspring properly lubricated, is the customer wearing the watch 12-14 hours a day and staying “active” etc.  No two people have the same activity level each day, some walk to work, some drive.  Some people work at a desk all day, some do manual labor etc.  You can’t compare apples to oranges when talking about power reserve on a watch.  For me if you wear the watch all day, take it off in the evening, it should be on time the next morning  approximately 12 hours later.  Expecting a watch to run for a day and a half on just a few hours of wear is asking a lot of any mechanical watch.