Encryption Problems

[Rockonmetal]

I have been told that I should encrypt passwords that are put into a database. I have been using md5. The problem I have is that when the user goes to log in the encrypted string changes. So when it looks at it, its not the same, so making it not be able to log in.
The question I have is this: Is encryption necessary for user databases with passwords, if so what is one that will stay the same? Or should I just make my own?

RESOLVED: *I had a typo in my code... *sigh**