f = FREEFILE
OPEN "input.txt" FOR INPUT AS #f

lineapedida = 7
cont = 0
DO WHILE NOT EOF(f)
   LINE INPUT #f, linea$
   cont = cont + 1
   IF cont = lineapedida THEN
      IF linea$ = "" THEN PRINT "The 7th line is empty" ELSE PRINT linea$
      EXIT DO
   END IF
LOOP
IF cont < lineapedida THEN PRINT "There are only "; cont; " lines in the file"
CLOSE #1