At first glance, it looks like you have a pretty good VI there. Do you have any questions or a specific problem with your VI that you need solved?
One comment I have is that you have a comparison to see if the string length is equal to 6 and you post a message that it must be greater than 6 characters if it is. What if you have only a 3 character password? It is not equal to six, so you won't get the error message. I think you want <= 6 to raise the error.
You don't have anything to detect whether the confirm password actually matches the first password entered.
Also, I'd recommend reordering the tab order on the front panel so that when you tab from the first password, it will go to the confirm password next, then go to Submit. Right now it jumps right to Submit.
Also, you may want to clear the Confirm password field as well as the password field after submitting the changes.
Also, what about upper vs. lower case. Do you want it to matter whether the username or the password have to be entered with the same case every time.
here is a password program:
it may help a little
i'd like thank you all for your help, but i was not clear enough when i addressed this problem, i looking to have this vi able to have one user to chang his password when he put old password right.
also i need to have limted user let says four user only
This might be a bit over the top for what you want as allows you to add multiple users but it is quite a nice toolkit and free to download