Q: If while praying two rakaats salaah, after sujood of the two rakaats, one forgets he has completed one or two rakaats and therefore stands up with the intention of praying one more rakaat and doing sajda sahaw but on standing he remembers accuratley that he in fact has completed two rakaats.
1. In this situation, while he has stood up with or has already started reciting Surah Fatiha, is it permissible to go to tashahhud or one should complete four rakaats?
2. Would sajdah sahaw be needed after completing four rakkats?
3. Or salah will not be valid and one must repeat it, if for example he was praying two rakaat sunnat muakkadah of Fajr or two rakaats Fardh of Fajr because he has prayed four rakkats instead of two?