ok, my son has a psp 2003 and i have downloaded games but only one of them plays. I bought a pandora battery and memory stick but that makes my one playable game not playable anymore. I just found a website that says to install custom firmware 5.50 gen d but don't know if its suitable for my psp or not. please help, getting so frustrated.How can I get the psp to play downloaded games. i have put it to only play games from the memory stick not umd.