OSX 10.5 Does not Recognize Login Password- Please Help!! This is insane!!

Question

Ok, so this problem is incredibly annoying and has got me perplexed. I recently re-installed Mac OSX 10.5 for various reasons.I am running a Macbook Pro that is 2 years old apprx. I did the following steps:
1. Booted from Install DVD (authentic)
2. Erased/zeroed out HDD
3. Installed OSX 10.5 on the Drive. And OSX is the only OS on the computer.
4. I went through the set up, and created a login name and password. The password is long, like around 30 characters. This is the same password I had used before, on the same OSX 10.5 from the same disk with absolutely no problem.
5. I slowly typed each character, having wrote each character down and did it for both pass and verification boxes on the initial screen when you boot for the first time and set up the user account.
6. This was all accepted, and I finished the process.
Now here is the rub, the password does not work! It logs in to my user name automatically using, I assume, the password I gave. But when I go to install my programs again, and it asks for the system password, it tells me the password is incorrect. I type it out completely and correctly off the piece of paper, and it says it is not correct. I have now retyped it 15 times, so there is no chance of it being a typing error (and same thing after re-re-install). ***!! I just put it in, what other passwords could it be!! I even erased the entire HDD clean a second time, and re-re-installed the OS and repeated the above. Still the same problem.
Can someone give me any idea what might cause this? I have tried everything I can think of, and cannot think of any cause.
Thanks everyone,
DpDimick
Message was edited by: DpDimick

Answer 1

Thanks again V.K. I did check the layout, and it was listed as alphabet when I inputted the password. So that doesn't seems to the the issue.
Just finished a truly mystifying experiment, but I put in a shorter password in the way mentioned earlier and it worked. I then systematically kept increasing the characters of that password and it seems that if the password starts to exceed about 16, it stops recognizing it. I am fairly sure it is not the password itself since it never gives an error when typing in the verification password. So unless I systematically make the exact mistake twice at the setup screen, and then don't or make a different mistake every time at the login screen, I don't think its my typing skill.
So problem solved for now, but I am still a bit worried. Maybe I should completely reinstall and use a shorter password.
Is there supposed to be a length limit?