This covers the 4th variants of dmsetup.exe, the mIRC Trojan Horse attacks. For more information, including a list of symptoms for these attacks, please see the main Trojan help page: trojan

Unfortunately there is still not a recommended fix for this attack. Because of the large number of files and folders that it creates, it probably makes the most sense to run a program to remove these. Several such programs exist, but so far none of their authors have been willing to provide us with the underlying source code. Without the source code, nobody can be sure what these programs really do. They might appear to fix your problems for now, but for all we know, they may also be installing other attacks or doing other forms of invisible damage, intentional or otherwise.

For the above reasons, we are forced to recommend the only safe fix for this attack: reformat your hard disk and re-install Windows and all your files from original distribution disks or secure backups. It’s not an easy fix, but then again you have broken your computer in a very real way by running this very serious Trojan attack. If a trustworthy, effective fix comes along in the future, we’ll be sure to pass that along.