when i turn my mac on and put my password in it goes all white how do i fix this

If your Mac boots up to the logon screen, and then, fails to go farther, one or more of the following may be the reason why:

• Launch agents (system, global, or user) are missing or corrupted.
• User login items are missing or corrupted.

Give the following a try:

• Boot up your Mac to the logon screen.
• Enter your user credentials. DO NOT press the login button yet.
• Hold down the <Option> key, then press the login button.

Please report back your results.

Also, maybe try starting up in Safe Mode to see if that works.