First, you need to make sure that you're using Adobe Photoshop CS3, CS4, CS5, or CS6 because the versions prior to these ones are not compatible with your operating system. After that, launch the program, select any tool from the Toolbox, right-click its icon from the Options Bar and select Reset All Tools. If it still doesn't work, select the rectangular marquee tool (the second one from the Toolbox), surround the area you want to be the cropped and then click Crop Image from the Image menu. If you still have issues, reinstall the program.
