I discovered that if you put the flash down, the camera figures out that you don't want the flash. In the automatic modes, you can disable the flash using the flash button on the left side and turning the thumbwheel. For some reason, the designers thought they would "make it easier" to disable in program and manual modes, so all you have to do is pop the flash back down. It took me about three weeks to figure out - and I'm an engineer!
Please don't hesitate to e-mail me if you have any other problems, Vianna. I've had my D-50 since June and have it pretty well figured out. Right, Chris?