Auto focus will work depending on the lighting. From my observation on youtube videos it seems that auto focus excels in bright lighting as opposed to dim lighting. Hope this helps take care.

Nope. The P/s is a function of the firmware, the shutter mechanism, the circuits, and the ability for the SD card to uptake the images as they are loaded from the camera, not added amperage/voltage. The max the camera can push to the best SD card under perfect conditions is about 6 P/s. The SD card must be at least a Class 6 (the '6' in "Class 6" has nothing to do with the camera's 6 P/s rate, by the way; it's just a "grade" for the SD cards). If the card is anything lower, it is unlikely it will be able to accept frames at that high speed. The camera matches its loading of the SD card with images with the ability of the card to consume the images. You will note that each time you take a picture with the camera, a green LED on the lower right of the back of the camera lights up. That indicates the camera is pushing the image to the card. In regard to the battery, only use the batteries meant for the camera in the camera or connected to it. If you try anything different, you stand a good chance of frying the electronics and creating a very expensive paperweight. Your owner's manual has a section on what batteries can be used. If the battery you want to use isn't listed there, don't use it.

Nikon cameras are manufactured in several places around the world. Look at the bottom of your camera body. It says the place of manufacture there. Mine was built in Indonesia. It works perfectly well, as you would expect a Nikon to operate. Remember, Nikon doesn't just hand off to factories. They carefully watch the quality and processes to assure that the equipment produced anywhere in the world meet their standards for that particular piece of equipment. Your warranty would be different between pieces of equipment manufactured in various places if Nikon didn't have complete confidence in their manufacturing facilities.

I have Windows XP and it works just fine. Agree with KeithD. Get the latest patches and updates installed, and try again. Don't worry about finding a specific patch. It's a good thing to update everything both from a security and a functional standpoint.

Page 319 of the D7000 User's Manual, which is downloadable if you do not yet have the camera, has a list of all approved memory cards.