Why is the shutter on my camera not opening after I took a picture?

I have a nikon fg 35 mm camera. I've already taken about 10 shots and I took a shot and the shutter closed and it's been stuck for an hour. I took of the lens and reattached it but still nothing. The view finder is black and I've used a few rolls with this camera and nothing's happened until now. I still have 3 more exposures left until the roll is done.

For some reason when the shutter OPENS and the mirror is raised up, you think that the shutter is closed.

If you are NOT using the light meter and shooting at fast shutter speeds, the mirror will not return so you can view out the lens until the shutter closes.

I do not recall, but if your Nikon FG has a Time feature on its shutter, the mirror will not come back down until you press the shutter release a second time.

Do you have a user manual?

If not, here is a link to one.

http://www.butkus.org/chinon/nikon/nikon_fg/nikon_fg.htm

Just based upon your problems and misunderstanding of how a 35 mm SLR works, you really need to take at least one class in photography before you get too frustrated.