We have no need to disprove any other religion. It is sufficient to simply say:

"I am Muslim because I believe in Allah(swt) and the truth of Allah(swt). I know the Qur'an is the True word of Allah(swt) and I know Islam shows us the way to follow his word."

Then we can explain why we believe the Qur'an is the truth. We do not need to prove if anything in any other scripture is false.