Questions abt Christianity

I've been out with a few friends lately. Had lots of sushi and food over the weekend. Many questions were raised while talking to my friends about Christianity. The same questions were repeated over and over again.

Here is a sample, answers anyone? I will be doing some research on these topics too. I think it is good knowledge to have.

Enjoy.

1)How was the early church formed?

2)Are Roman catholics, catholics? What's the difference?

3)What are the fundamental differences between Catholics and Christians? Do we all believe in the same God? Should I view a catholic as a brother/sister in Christ as well?

Are catholic practices right or wrong? Who is right? Christian or Catholic?

4)Do muslims believe in the same God as Christians? i.e Is Allah the same god as the God we believe in?

5)What happens when we die? Is hell an ever-burning place like the Lake of Fire described in the book of Revelations?

So many questions but so little knowledge. How long have I been a christian???