Yeah, Monster Hunter Freedom Unite was probably also the game I spent most time on my PSP.

It depends on what games you like, but I loved Persona 3 Portable and Kingdom Hearts Birth by Sleep.
If you liked Monster Hunter, you could also try God Eater. It is a really gold Monster Hunter Like with a good story!

Have you tried turning it off and on again?

It’s basically short for “Ferromagnetism”. So your guess with that is right. You can check the Wikipedia article about that topic, it explains quite well. I currently don’t have much time to give an ELI5. :(