Firstly - Hi everyone!

I'm very new to the forum, so I'll apologise in advance for any dumb questions!
Please bear with me though....

I recently found the PSP I bought a long time ago - thought I'd lost it/had it stolen a few years ago.

Its got the 1.5 firmware and Fastloader 0.7 on it.
When I got it, the memory stick already had two games (ISO's) in the ISO folder and they both worked ok - games were Virtua Tennis and Star Wars.

I downloaded a couple of ISO's - Football manager 2010 & Medal of Honour.
I put the relevant ISO's in the ISO folder on my memory stick.
Football Manager works ok, but if I try to start Medal of Honour - it just freezes before the PSP turns off.

I've since tried to put Splinter Cell & another ISO on there and got the same results.

Any suggestions?
I think I'm gonna have to put a different firmware on there, but am unsure of which one or how

Any suggestions or help would be greatly appreciated.

Cheers
Steve