Mail System Error - Returned Mail

[MAILER-DAEMON]

Dear user of linux.cz, administration of linux.cz would like to let you know the following.

We have detected that your account has been used to send a huge amount of spam messages during this week.
Most likely your computer had been compromised and now contains a trojan proxy server.

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

Best regards,
linux.cz support team.