Is there any way to change the Windows 7 password using the command prompt?

Type this command net user (your username) * Then type new password, and confirm it. You are done. See the image. In the image zack is my username. When you type the password the command prompt won't show the cursor moving as you type. Just type new password and press enter.

Use the "net user" command.

C:\>net user /?
The syntax of this command is:

NET USER
[username [password | *] [options]] [/DOMAIN]
         username {password | *} /ADD [options] [/DOMAIN]
         username [/DELETE] [/DOMAIN]
         username [/TIMES:{times | ALL}]


C:\>

See also here: http://technet.microsoft.com/en-us/library/8935e4a8-3624-46a1-b47a-c7735802b456
and here http://support.microsoft.com/kb/251394

Yes you could change the password with net user <username> <newpassword>.

Here further informations.