<p class="MsoNormal">In Fardh Salaat, it is Wajib in the first 2 Raka'at to recite Surah Fatiha and another Surah after it.<span style=""> </span>In the remaining Raka'at, reciting Surah Fatiha is Mustahab.<span style=""> </span>There is no command about another Surah.</p> <p class="MsoNormal"> </p> <p class="MsoNormal">Apart from Fardh, be it Sunnah, Witr or Nafl Salaat, it is Wajib to recite Surah Fatiha and another Surah in all 4 Raka'at.<span style=""> </span>Thus, another Surah should be recited after Surah Fatiha in all 4 Raka'at of Sunnah Salaat.<span style=""> </span></p> <p class="MsoNormal"> </p> <p class="MsoNormal"><i style=""><span style="font-size: 12pt; line-height: 115%;">Saying Aameen after Surah Fatiha</span></i></p> <p class="MsoNormal"> </p> <p class="MsoNormal">Saying “Aameen” after recitation of Surah Fatiha is a Sunnah.<span style=""> </span>If someone forgets it and the Imam recites another Surah after the Surah Fatiha, then the time for saying “Aameen” has passed and it cannot be compensated.<span style=""> </span>Sajda Sahw does not become Wajib on missing a Sunnah in the Salaat.</p> <p class="MsoNormal"> </p> <p class="MsoNormal">Thus, the Salaat of such a person will be correct, but he should be mindful of the Sunnah the next time.<span style=""> </span>It is given in Durre Mukhtaar, Vol. 1, Pg. No. 351:</p> <p class="MsoNormal"> </p> <p class="MsoNormal">Translation: It is Sunnah to say “Ameen” after recitation of Surah Fatiha.</p> <p class="MsoNormal"> </p> <p class="MsoNormal">Again, it is given on Pg. No. 350 of the same book:</p> <p class="MsoNormal"> </p> <p class="MsoNormal">Translation:<span style=""> </span>The Salaat is not rendered invalid on missing a Sunnah and neither does Sajda Sahw become Wajib.<span style=""> </span>However, doing so is not reasonable.</p> <p class="MsoNormal"> </p> <p class="MsoNormal"><i style=""><span style="font-size: 12pt; line-height: 115%;">Reciting another Surah before Surah Fatiha</span></i></p> <p class="MsoNormal"> </p> <p class="MsoNormal">If any person recites some other Surah before Surah Fatiha then that person should first recite Surah Fatiha and then some other Surah.<span style=""> </span>If that person has recited even 1 complete verse, then Sajda Sahw is Wajib (compulsory) on that person, as reciting 1 verse of the Holy Quran is considered as Rukn (article) of Salaat and if recitation of Surah Fatiha is delayed to the extent of 1 Rukn, then Sajda Sahw becomes Wajib.<span style=""> </span>If less than 1 verse is recited, then Sajda Sahw is not necessary.<span style=""> </span>As given in Radd Ul Muhtaar, Vol. 1, Pg. No. 340:</p> <p class="MsoNormal"> </p> <p class="MsoNormal">Translation: If somebody mistakenly recites at least 1 verse of some other Surah before Surah Fatiha, then that person should first recite Surah Fatiha, then some other Surah and perform Sajda Sahw.<span style=""> </span>Sajda Sawh has become Wajib because of delay in recitation of Surah Fatiha.<span style=""> </span>A slight delay, which is less than performance of 1 Rukn or less than 1 verse of the Holy Quran, is excused.</p> <p class="MsoNormal"> </p> <p class="MsoNormal"><i style=""><span style="font-size: 12pt; line-height: 115%;">Going into the Ruku after reciting Surah Fatiha only</span></i></p> <p class="MsoNormal"> </p> <p class="MsoNormal">Ruku means to bend.<span style=""> </span>The least limit of Ruku is to bend so much that the hands touch the knees.<span style=""> </span>If someone bends less than this, then this is not called Ruku and that person is considered to be standing (Qiyam) only.<span style=""> </span>That person can stand straight and recite another Surah (Dhamm Surah).<span style=""> </span>There is no need to perform Sajda Sahw (Sajda of forgetfulness).<span style=""> </span>Regardless of whether it is Fardh, Wajib, Sunnah or Nafl Salaat.</p> <p class="MsoNormal"> </p> <p class="MsoNormal">As given in Fatawa A'alamgiri, Vol. 1, Pg No. 70:</p> <p class="MsoNormal"> </p> <p class="MsoNormal">If someone bends to the extent that the hands just touch the knees, even then they can come back in Qiyam, recite another Surah and perform Sajda Sahw.<span style=""> </span>As given in Raddul Muhtaar, Kitab Us Salaat.</p> <p class="MsoNormal"> </p>