Those things which render the Salaah invalid

Crying in Salaah

Q: My father passed away 20 days ago. Alhamdollilah Allah Ta'ala gave me a lot of saber and I did not cry in front of anyone. But every time I pray namaz I just automatically cry. I don't know why this happens. I try so hard to control myself because I am scared that shaitan maybe making me cry. Is it ok to cry in namaaz?

Holding a hanky in one's hand and performing Salaah

Q: If a person is holding a handkerchief in his hand and performing salaah due to his nose running, his postures in salaah will be slightly changed, e.g. in sajdah he will hold his hand sideways or upside down so the hanky doesn't touch the floor, and in qadah his hand will be slightly lifted off his thigh with the hanky in between. Is it permissible to do so? What other options are there?

Switching off the phone during Salaah

Q: I know if a person's phone rings on loud during salaah, it is permissible to use one hand and switch the ringer off. If the phone rang very loud, and the person expects that it will ring again, someone mentioned that it will be permissible with one hand to take the phone slightly out the pocket, and look at the screen and press a couple things to switch it off (because today's phones can't be switched off without looking). Is this permissible?

Moving back in Salaah

Q: Two people are praying, with the muqtadi praying to the right of the imam. A third person then joins and pulls the muqtadi back to stand with him in a row behind the imam. When the muqtadi is pulled back, he ends up taking more than three steps due to the surprise factor (he takes about four small steps). Will this break his salaah?