I can't seem to put into context the idea how. Is it because the ISO is bad?

I don't really understand the question.

Are you asking why some games don't load at all?
In that case it is probably a bad ISO, yes.

few things can cause the psp to freeze when trying to load a game. the iso could be bad, i had to the psp speed on ratchet and clank because it wouldnt load and would freeze at the black screen.

it froze? Oh. It's the first time that happened to my psp that why. Is there a cure for it?

first time? what game is it? you might have to change some settings also.

monster hunter freedom.. i got the ISO from the DL section. Yeha, twas the first time it happened to my psp. What setting should I change then?

if you have a umd in your psp, and use no umd disabled already, you could also try changing the speed of the psp like i said ratchet and clank wouldnt load on mine until i changed it to 266 or 300... i forget what i changed it to. i was also told to try enabling plain modules in advanced but i dont even know what that does so i kept them disabled it worked fine after i changed the cpu speed.

i have had the same problem lots of isos work but some dont for example gta vc ssx nba moto gp i have ones that work too tho like socom 2 nhl and medal
and how do u change psp speed

Go to recovery mode (hold right trigger while booting PSP) and you will see it on the main menu, change it for iso/umd

also in recovery check what frmw your psp is running i fixed my little issue that way

is it by any chance related to HEN-C homebrew enabler? I already removed that image when I upgraded my psp from 2.71 fw to 3.03 oe-c. I thought I didn't have any use for it since 3.03 oe-c was said to play any and every game available.