for i:= 0  to neededseconds* 100  do 
   begin
          sleep( 10 );
          application.processmessages;
   end;

for (int i = 1 ;i< 4 ;i++) 
 { 
   Label1->Visible=true; 
   Label1->Repaint();
   Sleep( 3 * 1000 ); 
   Label1->Visible=false; 
   Label1->Repaint();
} 

for (int i = 1 ;i< 4 ;i++) 
 { 
   Label1->Visible=true; 
   Application->ProcessMessages();
   Sleep( 3 * 1000 ); 
   Label1->Visible=false; 
   Application->ProcessMessages();
}