How to play cso file on psp?

i hav a psp of firmware 5.03. i downloaded one cso file from mininova and i transfer it to my psp by creating a ISO folder.. but wen i go to games on psp it says no files.. so pls tell me how to play these games.. i read about the concept of downgrading...

I have a psp slim with custom firmware 3.71 m33-2. It has a 4GB sony memorystick. Last nite I formated the memory stick as I quickly wanted to delete everything. This isnt the first time I have formated it, but the previous times I backup everything...

if not what should i do to get the game running

I have final fantasy type 0 game but 2 iso file (I can convert it to cso file) I can't play it ,my psp shuts down ,someone suggest to compress iso file I think he/she says is to make 2 files to become 1 how do I do this?

Hi, can anyone help me please before i go mental. Ive just had psp flashed with custom firmware m33. Ive dowloaded littlebigplanet CSO file and places it in the ISO folder on the memory card (which is new and formatted first). I've shortened the filename...