How to kill a system process in Delphi

Hi Experts,

I've been trying to terminate a system process programmatically via Delphi with the following code:

function KillTask(ExeFileName: string): integer;
const
  PROCESS_TERMINATE=$0001;
var
  ContinueLoop: BOOL;
  FSnapshotHandle: THandle;
  FProcessEntry32: TProcessEntry32;
begin
  result := 0;
  FSnapshotHandle := CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
  FProcessEntry32.dwSize := Sizeof(FProcessEntry32);
  ContinueLoop := Process32First(FSnapshotHandle, FProcessEntry32);
  while integer(ContinueLoop) <> 0 do begin
    if (StrIComp(PChar(ExtractFileName(FProcessEntry32.szExeFile)), PChar(ExeFileName)) = 0)
       or (StrIComp(FProcessEntry32.szExeFile, PChar(ExeFileName)) = 0)  then
      Result := Integer(TerminateProcess(OpenProcess(
                        PROCESS_TERMINATE, BOOL(0), // BOOL(0) means 'false'
                        FProcessEntry32.th32ProcessID), 0));
    ContinueLoop := Process32Next(FSnapshotHandle, FProcessEntry32);
  end;
  CloseHandle(FSnapshotHandle);
end;

However, the above codes only works for programs/processes that are running under the 'normal' user account. The process that I'm trying to stop is being run with the system account. I did some research and found that some privilege settings needs to be done, so I've included the following procedure and called it before running the KillTask method:

procedure KillPrivilege;
var
  DebugValue:     TLargeInteger;
  tkp:            TTokenPrivileges;
  PreviousState:  TTokenPrivileges;
  dw:             DWORD;
  h:              THandle;
begin
  OpenProcessToken(GetCurrentProcess, TOKEN_ADJUST_PRIVILEGES or TOKEN_QUERY, h);
  LookupPrivilegeValue(nil, 'SeDebugPrivilege', DebugValue);
  dw := 0;
  tkp.PrivilegeCount := 1;
  tkp.Privileges[0].Luid := DebugValue;
  tkp.Privileges[0].Attributes := SE_PRIVILEGE_ENABLED;
  AdjustTokenPrivileges(h, false, tkp, 0, PreviousState, dw);
end;

But the process is still not terminated as expectedly. Fyi, the above set of codes are obtained from experts-exchange as well. Is there an error in the codes, or did I mis-typed anything?