Method Using Terminal...
Deleting files using Terminal requires extreme care; a little mistake can complicate things to a greater extent.
Step 1 - Open Terminal
Follow the following path to reach "Terminal"
Applications -> Utilities -> Terminal
Step 2 - Type "sudo rm –R" And Don't Press Enter
Type the above command without quotes and with a space after R. If you are not adding space after R, the command will not work. Remember to not press the "enter" key after typing the command.
Step 3 - Find the File That You Want To Delete
Drag that file to the Terminal window that you want to delete. This will add the filename and the path to it in the Terminal command. Double-check the file, before pressing enter to force delete file.
Step 4 - Enter Admin Password and Press Enter
When you are entering the password, nothing will show up. It seems like nothing has changed. Deletion takes its time, depending upon the size of the file.