alright, well there is a lot of questions on how to run ISO's on a 3.71 M33 pisp,so i will tell you how to do so.
1. Make sure all of your ISO/CSO's are in a ISO folder in the ROOT of your memory stick.
2. Make sure in your recovery menu, that the kernal is set to 3.71 fw
3. Now, when you boot up into the Pisp's xmb, press SELECT. Now, see where it says ISO VIDEO MODE, or something like that? switch it to SONY NP640 yadda yadda yadda.
4. Now, if you did everything right, go into your memory stick under game menu, start it up (like a normal demo) and it will play! yaaaaaaaaaaaaaaa.
thePSPhkr, i have had a few people come to saying there having problems with this guide..... it the first thing that comes up in a google search (run iso on a 3.71m33) so great job on the guide!! BUT seriously make corrections