Linux (Debian, Ubuntu, Centos) and FreeBSD systems
Login via SSH with the current password, then use the following command to change the password:
passwd

Windows Server operating systems
Login via remote desktop, then click on Start menu, open Control Panel. Here click on Change account type under User Accounts, choose the user then Click on Change password button.

In case you do not know the current password
Windows
You have to shutdown Windows, then you can request new Administrator password on our website.
In case of other operating systems
You have to write a ticket on our website to ask for a new operating system password.