Gameshark won't work with some self boot games? What?

[soundfx4]

Ok, I would first like to say that I had to repost this because I really didn't like the subject I gave my other post, and some people only have 56k modems, and can't just click every topic to see what it is really about. I would have deleted my other post, but I don't think I can, either that or I just don't know how to. Well thanks for understanding. now for my question.........

Hi, I have backedup games that are self boot. When I go to use gameshark with them (real one, not burned gameshark) some of them will work, others will boot up, and not work, and others won't even boot up. I am guessing the reason this is, is because gameshark is applying the codes to the boot sector, and not the actual game. But then why does the gameshark work on other self boot games? If anyone knows how to fix this, please let me know, thanks.