If Adobe Photoshop has frozen and become non-responsive, this means that your computer does not have the available system memory or processor resources available to run the program efficiently. This can happen if you have opened a number of additional programs along with Photoshop on the same machine. You can fix this problem by closing these other programs using the Windows Task Manager.
Open the Windows Task Manager by pressing "CTRL", "ALT" and the "Delete" keys on your keyboard until the Task Manager window appears. Windows Vista and 7 users need to click "Start Task Manager" from the window that appears on your monitor.
Click "Processes." Click the "Mem Usage" column to sort all processes on your computer by how much memory they are currently using.
Click on the application that is using the most amount of memory in the window on screen (so long as that application is not Photoshop) and click "End Process." This will close that program, which will allow the memory it was using to be used by Photoshop. Photoshop will now unfreeze and be usable again on your computer.