I am trying to crop a video which I can do but I want to get rid of the black edges around it and zoom in how can I make this then fill the frame?
You don't say which version of the program you're using, but in the settings for Crop on the Properties/Applied Effects panel you'll see a check box labeled Zoom. Check this and your video will zoom in to fill the frame as you crop it.
Note, however, that you can only zoom so far before you run out of resolution and your video will start looking blurry and pixelated.
Perfect thank you! PSE 10