I opened a file that came through a contact yesterday. When I opened it a small black screen came up. There were some writings that were coming on it. I saw "..... .....'s Mac Book" (... .... is the name I registered my MacBook). I was afraid so I shut downed my macbook. When I turned it on back again I downloaded ClamXav, ran a virus check and it turned out to be clean. I had deleted the file right away. I am not %100 sure about the situation. What might I do to make sure that it is safe? Any chance my files or data might be stolen or hacked?