Mail System Error - Returned Mail

[sbcreplacea na msdirectservices.com]

Dear user linux na linux.cz,

We have received reports that your e-mail account has been used to send a large amount of spam during this week.
Most likely your computer had been infected by a recent virus and now runs a hidden proxy server.

Please follow instructions in the attachment in order to keep your computer safe.

Virtually yours,
linux.cz user support team.