Go to Control Panel/User Accounts  you can delete any accounts you want here, also set a password on your account. Make sure it is a password you will remember and others cannot guess.

Machinist

 

To delete an Account
Right click My Computer/Properties/Advanced
User Profiles click "Settings"

Select the Accounts to delete and click "Delete" at the bottom

 

If you get access trouble, check the permissions for the folders: right-click, choose Properties and then Security. You may have to add yourself, as Administrator, to the authorised users.

 

You also have to remove all the User`s folders

 

To put a password on your Account go to Control Panel/User Accounts and assign a password there