Nikon D200 has become nearly impossible to grab images

It sounds like you have manually adjusted the aperture on the lens, letting less light in and hence a dark image in the viewfinder.

To be clear for your Nikon D200 battery,Nikon D200 battery charger and Nikon D200 battery life . You are possiblely find and solve the problem on Internet yourself,such as Nikon D200 charger.

You need to eliminate all the possibilities.
Does andifferent memory card exhibit exactly the same problem?
Sometimes memory cards develop faults.
If you can use the camera to format the card (You will lose all the pictures on the card when you do this) and take some fresh pictures, it may work. If not, buy a new card. The prices have come down so much now it makes sense to have several 1Gb cards so that you can have spares and swap them around.

Most cards work best if all the images are transferred to your computer or onto CD and then formatting the card to erase everything. If you do not do this the card may become unusable even if you have deleted individual images.

Try cleaning your sensor manualy.

its most likely to be the battery.

Camera must be in point-to-point USB mode for remote tethering to work.
In menu with wrench icon, make sure USB is set to "P" point-to-point.

http://www.nikonusa.com/Assets/Digital-SLR/25235-Nikon-D200/PDF/D200_Brochure.pdf

Link for the manual

You cannot crop images and save them on a D200. Thats what the Nikon Capture and Nikon PictureProject software are for. Here is the Cnet review link: http://webshots.com.com/digital-cameras/nikon-d200/4507-6501_7-31568586.html?tag=sub

You've made an excellent choice btw....

With your D200, you can use the kelvin temperature mode instead the other. As I work in TV where we do the white balance very often, I can guess what's the Kelvin temperature when I shoot. I only use Kelvin now on the D200 and it's more reliable!

I have bought two Nikon D300 in the past ten days, the first camera had stuck pixels, 12 of them, red dots in every image. The second Nikon D300 is so noisey in every ISO other than 100... it is worthless to me at this point. Sharp as a tack, but so noisey, the sharpness is moot. I think I have a solution, but it will involve dumping a $164,000 Nikon equipment history over the past 30 years and embroidering new patches on my photo vest which read, CANON! The fact that I even have to consider such a move makes me nausious. Nikon has betrayed many of it's biggest fans, me being one of them. I don't know what happened at Nikon to allow them to fall so far behind Canon, who trailed Nikon for nearly 40 years, but SOMEBODY SHOULD BE FIRED!!!!