Things You'll Need
Instructions
Connect your PSP to your computer with the USB cable and select "USB Connection" from the PSP menu. Most of the time the PSP will automatically go into USB mode, but if it does not, selecting this option will do that. You can now access your PSP memory stick from your computer.
Go to where you already saved the PSP ISO file and right-click the ISO file. Click "Copy" from the small menu that appears. Click the "Start" button on your computer and click "Computer." You will see the list of available drives, which will include your PSP memory stick.
Open your PSP memory stick and right-click the "ISO" folder at the top of the list of folders. Click "Paste" from the small menu that appears to transfer the ISO file to your PSP's memory stick.
Press the "O" button on the PSP gamepad to safely disconnect it from the computer. Go into the "Game" section on the PSP main menu and you will see your PSP game backup. Select it with the "X" button to begin playing.