Hello,
You can actually click up the user profiles on the other accounts that you don't need.
I will explain - user profiles are everything in the C:\users\username folder for that user. Cleaning the user profile will not erase the user. The user can still log in, but their user profile will be like new, like when the first time they used it.
To do so, you need to make sure your user has admin right. Then proceed to the following steps:
Hold down Win+R keys, type sysdm.cpl in the search on the taskbar and hit enter, go to Advanced tab, click on the "Settings" button at the User Profile section. This is where you can select the other user's profile and delete. Leave Default and Public profiles alone.