Salaah

Missing a waajib in qadha Salaah

Q: I know that if you miss a waajib in prayer, you must perform sajdah-e-sahw, and if you fail to do so, you should repeat the prayer, so long as its time remains. However, once the time for the prayer is over, the prayer is not to be repeated. What is the status of missing a waajib act in a qada prayer? If you miss a waajib in a qada prayer, and you failed to perform sajdah-e-sahw (or you performed sajdah-e-sahw incorrectly, i.e. you made only one sajdah), do you then have to repeat that qada prayer? Is it merely recommended to repeat that qada prayer or is it waajib to repeat that qada prayer?

Tawbah

Q: I have two questions I want you to help me with. May Allah Ta'ala grant you the ability.

1. I want to know how to perform istighfaar Salaah with full details.

2. And also, are there any particular Surahs to be recited or any particular prayers to be performed for one to get married soon? They have been searching for a good groom for me for the past one year but nothing is become finalized and is failing for some reason or other. I don't know why but Allah knows best.