well one thing you can do to help the 'cause' is to report the IP addy of the offender here: http://www.cphotline.org/

to really remove the file from your HDD, you will need an 'eraser' which will overwrite that sector of your disc with random data similar to a Department Of Defense (DOD) algorithm....Norton's SystemWorks will do this, along with plenty of other 'dedicated' erasers...