listen to them... when you do not know what it is or where it is from it is time to exercise the "delete"option... what's the worst than can happen? open it and you end up with nothing on (and I do mean nothing) on your hard drive and you are hosed (welcome to the full re-install and full file loss) or you can delete it and then if it was something important the sender will usually send it again...

as a rule of thumb "delete" is the way to go if you do not know who the sender is or if there is something attached...

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-Toast-
"It takes a lot of brains to enjoy satire, humor and wit - but none to be offended by them." -- Johnny Hart ("BC", cartoonist, 2000)
"Analyzing humor is like dissecting a frog: Nobody really enjoys it and the frog generally dies as a result." -- E. B. White