This text shows you how to change a user password on windows server 2008 (r2). Two options for you.
1. Run command prompt as administator.
2. Type in: Net User user_name password. For example: net user administrator pwd123.
1. Right My Computer, choose Manage.
2. Expand System Tools -> Local Users and Groups -> Users, and you will see all user accounts are listed on right panel.
3. Right click a user account, choose "Set Password ...".
4. Input new password on password field and click OK.