You are installing a new install of Drupal and during setup receive the error

Client does not support authentication protocol requested by server; consider upgrading MySQL client.

You are probably using MySQL 4.1 or higher and need to reset the password to pre 4.1 style.

There's a quick way to fix this if you use recent versions of PhpMyAdmin and have the rights to edit MYSQL user information:

1. Select the 'privileges' option on the main PhpMyAdmin page
2. Edit the user you're using to connect to the Drupal database
3. Scroll down to where it says 'Change password'
4. Enter and re-type the password for that user
5. IMPORTANT Where it says 'Password Hashing', choose the option that says 'MySQL 4.0 compatible'.
6. Save your selection

You should now be able to connect to your Drupal database using that user and password with no more errors.