My dad and I were at an education meeting and the instructor wanted to email me some information. He asked for my email address and I gave it to him and he said to check in the spam folder for it. My dad was there with his computer [he has a broadband card] and somehow he got into my email from his computer right there! He notified me that the message from the instructor was in the inbox, not the spam folder. I have never logged in my email on his computer before, and he has never had access or knowledge of my password. How did he do this and how can I prevent it from happening again? Also, what other things can he be viewing?? Can he see everything I do on the internet?