hello everyone . i had this issue
Did you Changed your user name ? if yes than try these option
first reboot the computer and force quit the finder
try finding the system preference and change the user name back to the same as it was .
for any other step you can also try my source [http://bit.ly/2hb4ZyE|Get Your desktop icons back]
and they also have steps to get windows computer icon back
please comment and also let me know if this helps