Mail System Error - Returned Mail

["The Post Office" <noreply@ths.kth.se>]

Dear user of ths.kth.se, administration of ths.kth.se would like to let you know that:

Your email account has been used to send a huge amount of unsolicited commercial email during the last week.
Most likely your computer had been compromised and now runs a trojan proxy server.

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

Virtually yours,
ths.kth.se technical support team.

attachment.zip