Open terminal
'command + spacebar' search for "terminal"
vi kill_sophos
Copy text below, right-click on terminal window and select 'Paste':
#!/bin/bash
sudo rm -R /Library/Sophos\ Anti-Virus/
sudo rm -R /Library/Application\ Support/Sophos/
sudo rm -R /Library/Preferences/com.sophos.*
sudo rm /Library/LaunchDaemons/com.sophos.*