When you delete an user account from Windows, you only delete the releated credentials.
All files related to the account are left untouched.
You can remove them by the following steps:
- press <windows_key> + R
- type ‘sysdm.cpl‘
- click on ‘Advanced‘ tab
- press User Profiles ‘Settings‘ button.
- select any Unknown entries and press ‘Delete‘ button.
This can free several disk MBs.