OK I know it's been written in lots of other threads that there are no known mac viruses, is everybody completely positive about this? Because it appears that my Mac may have caught one. Whenever I email attachments (tends to be word documents but sometimes photos too) from my computer to friends or colleagues who run anti-virus software on their PCs, it blocks the email stating it had detected a virus. Coupled to that, my Mac is starting to shut down without any warning. Something strange is going on. I haven't installed any anti-virus software, for the simple fact that almost every forum or magazine article, suggests there is no need, so I don't really know if I do or do not have one. Has this happened to anyone before, or does anyone know a solution? Could it be I have a virus??? Please help. Thanks.