I changed my user account name and now my laptop is unable to boot up.

Hi Susan;

Thank you for updating me with that information, I would recommend creating a new profile user rather than modify the username because this will effect with registry keys files and could be effect changing from permanent to a temporary profile user.

The solution is login as an admin or Administrator then follow one of the methods below:-

Method 1:-

• Hit "Windows Logo" and type "Control Panel"
• Click "User Accounts" then click "Add or Remove Account"
• Create a new account then put it as the Admin group.
• Log-off then log-in with the new one and delete the old profile

Method 2:-

• Hit "Windows Logo" and type "Control Panel"
• Click "System and Security" then click "Administrative Tools" and open "Computer Management"
• On the left-sidebar click "Local users and Group" and Right-click on "Users" select New User
• Create the user then Right-click the one-created select "Properties"
• Select "Member Of" then click "Add" then click "Advanced" then click "Find Now"
• A list will appear such highlight on "Administrators" then click OK then OK and OK
• After that log-off and log-in with the new one then you can remove or delete the account.

Let me know if you need any assistants

Please tell me a solution, how can i solve the problem.

These are the error getting (screenshots) when i am trying to start my laptop.

Stop Code- CRITICAL PROCESS DIED

The problem is is due to what i did is, first pressed Windows key+ R, then type netplwiz and pressed ok like the screenshot.  

After that a new window opened like the below screenshot.

The screenshot have many users...but i have only one user name which was administrator user. Then i select the user and click on properties and change the user name to Susanta, which was previously susan. 

After that when i again go to the user section by pressing Windows key+ R , and then type netplwizi did not find any users. Then i restart the laptop. After that the problem occers.the laptop did not boot up.

you are looking for the settings in the Run.. program systempropertiesadvanced

user profiles.

there problem will still persist there as the options to delete and copy to may not be available.

it has to be easy. in the case you have a problem with no available options. the solution must be in the environment variables. there are a bunch of temp directories that are never administrator specific but are user included.

Hi Susan;

Thank you for the update, at the moment are you able to log-in the account or not?, also what is the name of the account you changed?