Press shutter button and r07 flashes and I can't take the photo?

Any help of what to do to fix this? New to photography.using a aNIKKOR 50mm 1.8G lens on a nikon D40

There probably isn't enough light where you're trying to shoot for the camera to autofocus properly. Switch to manual focus, or shoot where there's more light.

BTW, r07 isn't an error message. It's how many shots you can take before the camera's memory buffer is filled.

Do you have a manual for your camera? If not, you can view it on Nikon's site here: http://www.nikonusa.com/...oprint.pdf It's an invaluable resource for troubleshooting information.