Can I prove God? Did he Give the Torah?

As a "rationalist", who is critical of Rabbinic fallacies, I am often asked by my  skeptical friends, whether I can prove that God exists, and furthermore, whether the Torah was indeed given to Moses by God, and if I can prove this scientifically or not?

I've looked at various  arguments provided by Rabbis, orthodox philosophers and scientists, computer analysis, as well as counter arguments by  reformists, secularists, agnostics and scientists.

As yet, none of the "proofs"  have proven much, and the disproofs produce doubts. Indeed, I once asked Lord Jonathan sacks (before he became a Lord, and before he became Chief rabbi) if he can prove the Torah. His answer was No. But he said it is the best lifestyle he has found.  And it certainly  helped him, as he received a peerage and now gives after dinner talks for good reward.

If I cannot prove the Torah, then how can I convince others to live by it? My argument is that today, we have no prophets, and no open communication from God. Thus only in the times that this did occur (if it in fact occurred) would there be a real proof of the Torah.  However, even in those times, there were people who denied that prophecy, and may have lived lifestyles dedicated  to Baal or other idols. So, today, would an Old Testament styled prophet be accepted? Could his miracles or words persuade the skeptics?  We know that Elisha and Elijah did not have unlimited superpowers, and they both were chased down by enemies, with Elisha being imprisoned.  So, presumably today he could also be imprisoned in Gaza or Kiev.    And the miracles performed by Daniel have no independent corroboration.

So how can I argue that Tanakh is true? And of what use would this be to someone who cannot live according to the Torah, eg the many LGBTs that are prevalent today?

My only strategy is some kind of Pascalian wager.  As we get older, there is less left in this world to hold on to.  On the other hand, part of the same wager would be to reject the additional rabbinic laws, which hinder us an deny many permitted [by the Torah] pleasures, eg live music, women's voices and enjoyment of life during the Omer and 3 weeks of mourning (the rabbinic Ramadan).

I have no proofs, and it is not for me to bring any.  The "onus" is on God to bring prophecy back to Earth.