Dark Nikon D90 aperture problem

I'm just starting out with playing on the A mode of my Nikon D90, problem is, all my images are coming out really dark, and i don't know why, also, i can't seem to change the aperture, i move the swirly dial on the front and look through the view finder, but nothign happens:/

Photographing ceramic artwork for jury into fairs what lens do i use on nikon d5000?

Need clear steady detailed photos

Tamron lenses for Nikon D60 - Any issues, feedback?

Tamron lenses for Nikon D60 - Any issues, feedback

Does my card need to be reformatted?

None of my computers are reading my Nikon D70. I have over 900 photos on this memory card.

Whenever I plug my camera into the computer using Linux OS it says

"Sorry, could not display all the contents of "NIKON DSC D70": DBus error org.freedesktop.DBus.Error.NoReply: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken."

There are lots of photos on this camera that I need. Are there any ways to save them or get my computers to read my D70?

What can I improve from this picture?

Camera: nikon d90

The image above was my first photo shoot by myself. And i move the settings around, which it listed below for my clothing website. I'm fresh with photography, please tell me what should I improve in the camera settings and lights. Thanks.

-shutter:30
-aperture: f8
-exposure compensation: ±0
r13 (i don't know what is this)

Nikon d3000 how to shoot for soccer?

I got a nikon d3000 to take pictures of my kids soccer games but i can't seem to get a clear picture as they are running by. I know it has something to do with shutter speed and stuff but i'm all too very new at this stuff. Could someone help me figure out the settings i need to set it to? Also would like to know how to get clear pictures at night when they are playing.

Nikon D3000 problem with taking pictures?

I bought this Nikon 2-3 weeks ago and was working like a charm! Today a friend came and wanted to see the camera and i took some pictures to see the quality. In the 3rd picture it was black. I said thats odd. I took another picture and was black too! I suspected something on the settings or something but it was ok within those minutes, i was taking pictures and suddenly blackness! I reset the settings and still the same. I removed and replaced the battery and the lens i changed memory card and still black! It couldnt be more black than this!
Does anyone know what's going on here?
Please help! Thank you.

Added (1). Fhotoace with respect on your experience, i said that i was taking pictures and the 3rd picture taken it was black! With out changing any setting! I even reset the settings! I took a picture of the sun too and its still black! Not a single white frame in it. The settings are exactly as it was the first time i used the camera

Added (2). Jim A, thank you Jim i really appreciate your effort! Where can i send the good & bad pictures so you can get it?

What's the correct setting for Nikon D5000 when using reverse kit lens? - 1

I bought a reverse kit lens adapter for my Nikon D5000 so I could do macro shots but even with the adapter, the camera says NO LENS ATTACHED. It switched to manual focus and truned VR off but it's still the same.

I need a few pointers?

I'm just starting night photography and I'm using a Fujica ST705 Manual SLR with a standard 55mm lens, a 75-260mm lens and a 35mm lens. (As well as a Nikon D90 but I'm hoping to use a Manual SLR for the most part).

Is this an okay camera to use? What films would you recommend?

Any other tips you've picked up would also be useful, I'm eager to capture good images, I'm just a bit of a newbie.

What is the Price of a Nikon D80 in Bahrain?

I'm planning on buying a new camera. So I just wanted to know around how much a Nikon D80 costs. If you can tell me the price in dollars, I'm fine with it too!
And I'd also like to know, which one is better a Nikon D40 or D80. I know that the D40 is only 6.1 mp, while the D80 is 10.2. But what I mean is leaving Mega pixels apart, which do you think I should buy.