No, it's impossible for them to directly affect the PSP. The worst that could ever happen (and this could happen at any time, even while saving a game) is the memory card becomes damaged. But otherwise, they can't affect the PSP's firmware.
It can sometimes mess up your computer. So its not great, but its not bad.
It shouldn't.
No, not at all. It requires no Downloading.
No, your good, you can go ahead and cheat away, but if you are trying to modifly your psp like putting a chip that lets you use burn games than beware because you could mess up badly.
Probably
Ya minecraft may mess up your PC because that software doesnt have SSL certificate's.which is used for secure transaction.
ISO is the format in which the games of the PSP is saved as.Most of the PSP games are in ISO or CSO.So if you search for PSP ISO in a search engines, those that came up are probably PSP games for downloads.
If you mean Iso and Cso games, they don't show up because your psp doesw not have CFW or does not have compatible CFW.
No: but they will only run if you have 1.5 ofw or any version of cfw.
Yes you can as far as your firmware is up to date!
Your PSP is then a useless "Birck". It can be reverted to a prior firmware but it is very very long and excruciatingly painful process to do.
Go to the PlayStation Store or download demos. You have to sign up with the PlayStation Network to access games and demos. This can all be done on the device and is very simple. Before downloading a game or demo make sure you have strong Wifi connection as games take a while to download from the PlayStation Store or go to HMV.