uses
   Windows, OLEAuto;
 
 procedure OpenInternetExplorer(sURL : string);
 const
   csOLEObjName = 'InternetExplorer.Application';
 var
   IE        : Variant;
   WinHandle : HWnd;
 begin
   if VarIsEmpty(IE) then
   begin
     IE := CreateOleObject(csOLEObjName);
     IE.Visible := true;
     IE.Navigate(sURL);
   end
   else
   begin
     WinHandle := FindWindow('IEFrame', nil);
     if WinHandle <> 0 then
     begin
       IE.Navigate(sURL);
       SetForegroundWindow(WinHandle);
     end
     else
     begin
       // handle error ...
     end;
   end;
 end;