I think you're trying to run before you can walk. You need a good understanding (or at least an idea) of ASM, Windows API's and the PE file structure first
Softice is probably a must as well!
There are some good tut's on Safedisc as well, so you may be lucky and be able to understand them.
THEN you can think about Safedisc
Or you could just 'reverse' bOOl's cleaner and cheat
The reason there are differing versions is simply to stay one step ahead of the crackers. A new version will theoretically need more time to 'crack', but we all know that's a load of s**t as they usually get cracked the same day
DrA.