Reciting in one's mind in Salaah

Q: A few years had passed where I used to recite Qirat and tasbeehaat in Salaah silently. Do I need to repeat all those Salaah? Most of my Salaah I performed was with jamaat. However, in that 8 year period I am not sure how many Salaah I performed individually. How would I calculate how many Salaah I need to redo in this instance?

Reciting Qur'an while driving

Q: I read in seeratun Nabi that the worst person is he who reads the Quran without attention. I usually read three paras a day whilst driving, but most of the time my attention deviates. Should I read less and try to focus more? Will I be punished rather than receive reward for all the recitation without attention?

Wali for a revert Muslim

Q: I got a question about marriage. I have recently met a girl that has reverted to Islam, and me and her we want to get married, I am a muslim, my parents approve, but her parents are non-muslim and do not approve her getting married. So I was wondering who will be her Wali, as nobody in her family or house hold are Muslims. How do we do it with witnesses when we are doing nikah and she is 18 so its legal.

Rejecting the Hadith

Q: I am working in Birmingham city university and some of my Muslim colleagues due to spending most of his time around non believers are a bit away from deen. He has this objection against hadith that we should just follow the Quran as its authentic and not Hadith. I do try explain him that without hadith one cannot understand Islam. Can you please help with it as you can provide me some verses from Quran so that I can relate it to him and any other means to make him understand.