ISO/CSO's do not execute

[Geneman]

Hey Chaps,

Up until a few weeks ago my PSP was running happily on the 3.52 CFW firmware. I attempted to load a few themes on the memory stick but this did not work. So I deleted all the 'Themes' folders I created but ever since then none of my iso/cso games execute. The screen remains blank for a minute or two and thereafter reverts back to the main screen. I reformatted my memory stick and even update to 3.53m33-4 but the issue is still persistent...
Please help...
Thank You.

Gene

[Switchblades]

What games are you trying to play? Some games wont' run on 3.52.

[Gameunreal]

upgrade to 3.9033.

when u are at that firmware make sure to select np9660 as your umd driver.

if you dont want to do that, in recovery menu select the umd driver option as disabled, then try running a game with a umd in the drive