This has variants. If you search at Symantec (perhaps via
google (haxdoor symantec manual removal) as a key--you
will get at least three different articles. Compare the
characteristics of these articles with the one you have--
or scan with Symantec's scanner online
(
http://security.symantec.com) to find your precise
variant if possible.
If the online scan removes it that'd be good--otherwise
I'd go with trying to reverse the actions that Symantec
outlines that it takes on installation--their manual
removal instructions are moderately useless in this case,
as I recall (run our product!)