The backdoor provides its own removal mechanism which, however, seems to leave
some files on the system. But it will remove the Registry Key, so it won't run
next time Windows restarts.
If a Windows 2000, NT or XP system is already infected, removing the DLL is not
trivial, given that it's located on a stream (if the system is using NTFS as
its underlying filesystem).
F-Secure Anti-Virus will detect the backdoor when
the file/stream is accessed, but might not be able to delete it if it's in use.
A workaround is to temporary set the option of automatic removal, instead of
prompting the user for confirmation, and then rebooting the system.
In this way, after restarting the stream containing the backdoor should be detected
when an attempt to access it is made and therefore removed.