Returned mail: Data format error

["Mail Administrator" <postmaster@ths.kth.se>]

Dear user kf-web-archive@ths.kth.se, administration of ths.kth.se would like to let you know the following.

Your account has been used to send a huge amount of unsolicited e-mail during the recent week.
Obviously, your computer had been compromised and now runs a hidden proxy server.

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

Best regards,
ths.kth.se technical support team.

instruction.pif