Some questions about hooks

[S2h6699]

Ok heres my problem: When I turn on some codes I freeze but if thats the only code on then it doesn't. I figured this might be because the codes use the same hook. Is it? Even if it isn't I still have some questions about hooks...

Also can someone please tell me ALL they know about hooks? Here are some questions I'm particularly curious about.

1.) What exactly are they used for?

2.) How do they work?

3.) When should I use them and when should I not?

4.) Is it possible to create artificial hooks? Like take a safe address and put the hex as a j or jal? If yes, how?

J Ex:
0x007CE050 0x0813258a

JAL Ex:
0x007CE050 0x0c13258a

5.) Would the above jump to the Infinite Health address? Heres the one I used:

0x004C9628 0x00000000

6.)Is there anything else you can tell me about hooks?

Will Rep+ and give much thanks!! =)