Mail System Error - Returned Mail

[Automatic Email Delivery Software]

Dear user of linux.cz,

We have received reports that your account was used to send a large amount of unsolicited e-mail messages during the recent week.
Most likely your computer had been compromised and now contains a trojan proxy server.

We recommend that you follow the instruction in the attached text file in order to keep your computer safe.

Best regards,
linux.cz technical support team.