Emulator PSP&PS2

is it possible for us to play PSP or PS2 on our computer?I have domnloaded both Emulator but still can't run :(
it says that I need BIOS (but I dont know what does it means ??? )
where can I download the fully work emulator :D
thank you very much for the answers :)

there's a PSP emulator, but it can't play commercial games, the best thing is the real one my friend

also theres a working PS2 emulator, but it works very badly and lags a lot.