2. "How can you believe in God, when you can't see, hear, touch, smell, taste or even imagine what He is?"
We know from the teachings of Muhammad, peace be upon him, that no one has ever actually seen God - at least not in this lifetime. Nor are we able to use our senses to make some kind of contact with Him. However, we are encouraged in Islam to use our senses and our common sense to recognize that all of this universe could not possibly come into existence on its own. Something had to design it all and then put it into motion. That is beyond our ability to do, yet it is something that we can understand.
We don't have to see an artist to recognize a painting, correct? So, if we see paintings without seeing artists painting them, in the same way, we can believe that Allah created everything without having to see Him (or touch, or hear, etc.).