I have a problem. I downloaded a game "Final Fantasy 7", its in .CSO format. I put it into my "ISO" folder and when I try to load it in my PSP it looks like it loads but then says can't load the game and some numbers in brackets. I did a little research and I found a youtube video, of some guy having the same problem. He fixed his problem by putting any UMD disk into the PSP. So my question is, am I missing an addon to play CSO/ISO games? or do I just need any kind of a UMD disk in order to play games? I really don't want to buy a UMD disk. If anyone got a solution to my problem please help!