Newbie question of the day

[Serpent]

Ok, so i buy a Ps2 from walmart which most likely will be v7. This will be capable of playing only ntsc games.

Suppose i want to play PAL games on this, a game bought from Hong Kong let us assume.

Will just having a messiah 2 PRO (compared to the regular Messiah) do the trick or will i have to use one of those "patches" i keep on hearing about?

Basically, what determines if you can play PAL on a NTSC system? The mod chip or something else?

TIA!!