How do I take a picture and not a video?

It keeps taking a video and not a picture. I just need a picture, not a video..

Assuming you're asking about a computer and not a camera and you're using Windows, Hold down Ctrl and Print Screen on the keyboard. That will copy the image to the Clipboard.

Load a photo editor program, make a new file and select Paste. Then Crop it if needed and save it.

If you don't have a photo editor, Use MS Paint on your machine at: Start/Programs/Accesories/Paint

Understand, I'm just guessing at what you're trying to do. A more specific question gets a more specific answer. :-)