Using a patch (I'm a newbie!!)

[IKO]

Have tried to copy MY copy of Mission Impossible (PSX1). It works fine during the credits but when the game begins, it just hangs!
It is a "protected" game so I have downloadede the patch for the program .... NOW, how do I use/install the patch to overcome my problem?
1. Do I have to create a game image first and copy the patch to that file?
2. Do I copy the PSX CD to disk and then copy the patch to that?

When I try to use the patch, it says it is a System file! What do I do??

Help please!!

IKO