Returned mail: see transcript for details
Body of Email:
Dear user of yourdomain.com, (yourdomain would be your actual domain)
We have found that your account was used to send a large amount of unsolicited commercial e-mail during the last week. Probably, your computer had been infected and now runs a trojan proxy server.
We recommend that you follow the instruction in the attached file in order to keep your computer safe.
Best regards, The yourdomain.com support team.