"SELECT COUNT (one, two, three, four, five) FROM $this->tablename where username='$username' and one='Not done' and two='Not done' and three='Not done' and four='Not done' and five='Not done'"
Try this one:
SELECT (one='Not done') + (two='Not done') + (three='Not done') + (four='Not done') + (five='Not done') AS num_not_done FROM $this->tablename where username='$username'
(column='Not done') will return
0. So you can just sum the results to get the count of matches.