I do not know what means "change an account on w2k service"
Am I right that this is just user account?

Here is a code borrowed from "Perl for System Administration" book that creates an account, modification of an user is quite similar to it

use Win32::OLE;

$ADsPath = "WinNT://_enter_domain_name_here_/_enter_computer_name_,com
+puter";
$c = Win32::OLE->GetObject($ADsPath) or die "can't get $ADsPath\n";

# create & return User
$u = $c->Create("user","xx");
$u->SetInfo();  # first create object for user, and thenchange values

# in WinNT: a space between "Full" and "Name" is impossible
$u->{FullName} = "XXX-user!"; 
$su->SetInfo();
[download]

A point is to use Win32::OLE for WMI, which is a central point for Win2K administration manupilations.

Best wishes,
Courage, the Cowardly Dog