You have logged in with administrator, but you are still prompted that you need administrator privileges to delete files
No software support required!
First, find the file or folder you want to delete, then right-click on the file or folder, select Properties, select Security, Advanced, Owner, Edit, and then select the user you are logged in at this moment. Come over, right-click the file or folder, select Properties > Edit > Select the user name you are logged in to at the moment in the group and user name, and then select the user name to allow, obtain full control permissions. File or folder can now be deleted
The purpose is to allow the logged-in administrator to have complete independent control.