unction NetServerEnum(const ServerName:PWideString;level:DWORD;var Buffer:Pointer;
         PrefMaxLen:DWORD;var EntriesRead:DWORD;var TotalEntries:DWORD;ServerType:DWORD;
         const Domain:PWideChar;var ResumeHandle:DWORD):DWORD;stdcall;external'netapi32.dll';
function NetApiBufferFree(Buffer:Pointer):DWORD;stdcall;external 'netapi32.dll';
function GetSQLServerNames:TStrings;
type
  TServerInfo101=record
   platform_id:DWORD;
   name:PWideChar;
   version_major,version_minor,server_type:DWORD;
   comment:PWideChar;
  end;
  PServerInfo101=^TServerInfo101;
var Buffer:Pointer;
  EntriesRead,i,ErrCode,ResumeHandle,TotalEntries:DWORD;
  PDomainUnicode:PWideChar;
  ServerInfo:PServerInfo101;
begin
  Result:=TStringList.Create;
  ResumeHandle:=0;
  PDomainUnicode:=nil;
  errCode:=NetServerEnum(nil,101,Buffer,DWORD(-1),EntriesRead,TotalEntries,4,PDomainUnicode,ResumeHandle);
  if(errCode<>0)then raise EWin32Error.Create('Can''t enumerate servers');
  try
   ServerInfo:=Buffer;
   for i:=1to EntriesRead do
    begin
     Result.Add(ServerInfo^.name);
     Inc(ServerInfo);
    end;
  finally
   NetApiBufferFree(Buffer);
  end;
end;
 
procedure TForm1.Button1Click(Sender:TObject);
begin
  ComboBox1.Items:=GetSQLServerNames;
end;