If you do not know the sender... don't even open it... much less any attachments that are included.
I'm kinda old school... for such a youngn' If I don't know you... I'm not likely to respond to you. (But that doesn't explain my presence here now does it?)
I use Outlook Express as my eMail viewer, and with it, I can actually view the contents of any eMail without actually opening it.
Many a Virus have been thwarted by my Norton Internet Suite, but occasionally one will enter my Inbox. If for some reason I think that it's possible that this eMail may have come from Family (don't know all their eMails) or from one of my HOG members (I'm on the Board)... I'll use the 'right click' option to check the eMail's properties... then select "Message Content". It places the content of the eMail in a viewable source where I can actually read it, and see the Code for any attachments without actually opening them.
When I notice that it's potential 'Spam' or worse, I will then run a virus scan on the individual eMail. Norton then lights up will all the details and has learned a new source to avoid.
Most of the time, I simply delete them... if it was important from the beginning, I'll expect an actual phone call... otherwise DELETE AWAY
