function GetUserName: String; 
 var 
   Buffer: Array[0..MAX_PATH] of Char; 
   sz: DWord; 
 begin 
   sz:=MAX_PATH-1; 
   if Windows.GetUserName(Buffer,sz) then begin 
     if sz>0 then dec(sz); 
     SetString(Result,Buffer,sz); 
   end 
   else begin 
     Result:='Error '+IntToStr(GetLastError); 
   end; 
 end;