Over the past few months I have recieved a number of emails that look like they are from a legitimate UK company, claiming that I have an overdue / outstanding Invoice to pay.
The email looks very legitimate as not only does it have a email signature from a real company but also includes a footer note that suggests the email has been scanned by an antivirus program and that it is certified "clean".
Unsuspecting recipients will try and open the attached "invoice" only to then infect their computer with a virus.
If you reciveve one of these emails – delete it and dont panic. Providing you dont open the attachment, your computer is safe.
However, if you end up finding that these spammers/scammers have used your email address to send fake emails – you will probably find out when you start getting bounce back emails and emails from people telling you they dont owe you money! (like I did yesterday)
There is a 95% certainty that they have "spoofed" your email address (setting you as the sender) and have NOT hacked your email or computer.
(Having said that its always worth getting your PC / Email account checked just-in-case)
If it helps, you can ask your email provider (usually your web designer or web hosting company) to setup something called a SPF record, this will help stop people (scammers) from spoofing your email in future.