Pass word protecting Mac w/o encrypting files

I have a 13" MacBook running 10.5.8.

I want to be able to password protect the use of my MacBook.

I have used the pass code thing that involves File Vault where the computer's files are encrypted upon shutdown and then unencrypted upon startup (once the code has been entered). That encryption and unencryption process is quite time consuming and I would like to be able to just enter a pass code without any encryption taking place. How do I do that?

Thanks.

 

Got it! Now how to change password?

Ok, I got it. Thanks a lot. A password window came up immediately after the computer booted.

Now how do I change the password?

Thanks.