Tricky one, there are variants. It has attempted to arrive in my home computer, we might or might not have been attacked at the office. We received an email saying we had sent it, except I have read that it can forge email addresses of senders so it might not come from who you think!
Also today I received this from my daughter who is at university - this is part of the warning they received from the university computer section. Sometimes the subject line has lady in it. See
www.snopes2.com - then go to computers. It can actually arrive as a promise to make your computer immune! If you get something like the following don't open it - only use a well known site for a cure, such as Nortons or McFee.
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Subject: Worm Klez.E Immunity
Klez.E is the most common world-wide spreading worm. It's
very dangerous by corrupting your files. Because of its very
smart stealth and anti-anti-virus technic,most common AV
software can't detect or clean it.We developed this free
immunity tool to defeat the malicious virus. You only need to
run this tool once,and then Klez will never come into your PC.
NOTE: Because this tool acts as a fake Klez to fool the real
worm,some AV monitor maybe cry when you run it. If
so,Ignore the warning,and select 'continue'.
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Now is that sneaky or what! Klez is a real nasty, you just don't want to get it.