It is interesting that how we human with a little brain try to evaluate things, where as scientists and other intellectuals, who have been given more power to use their brain (compared with a normal human), is in view that there is a power who runs all the business of this universe.
Answer to the question that “if there is a GOD” and how to prove it, is that is there any thing like DARKNESS exist? The answer is that there is nothing like DARKNESS but when there is no light its called DARKNESS. Is there any thing “cold’ exist, no but when there is no heat it is called COLD. Can we see cold or darkness NO but we know that if there is no LIGHT it is called darkness and if there is no heat it is called cold.
No body saw GOD but different experiences tell us that there is a POWER who dominates this universe.
All Religions are a chain of a command and has been sent to human in different time. Moses, Jesus and Mohammed (peace is upon them) were given guide lines (holy books) to set up a better society on this earth. In fact the power (ALLAH, GOD or call him by any other name) is one but the messengers of him with guide lines were sent in different times for only one purpose. The problem is always created by the followers when the acceptance of some thing new vanished from them.
The LAW of the power ALMIGHTY is that we must do the justice among the people. Take any war (which have been discussed in the thread) were fought not for religion but when people started injustice. Followers of any religion were never given any authority to kill each other but yes it was asked by all the humanity that “when you see the injustice is done try to fight that out by all means as the injustice is the basic cause of any problem.
Take any example and start it from home. If there are four brothers and one of them is not handled equally, obviously being human he will try to get his RIGHT all means and if not given then no blame goes to him if he seeks help even from outsiders against his own blood and flesh. We can see examples in our every day life. Yes, most of you right when you say that the religion is made the base of any fight or war, where in fact if the justice was done by the CROWN AND CHURCH OR CROWN AND MOSQUE then there would not have been a problem.
Now days European or call it western especially in UK and Scandinavian countries the justice system is appreciate able NO DOUBT. See the basic is the justice over there which does ease thing for their generations. Believing God or not that is a different matter but we can not blame religion for KILLINGS OR WARS BUT WE CAN BLAME INJUSTICE FOR THAT.
Bible was a true word of GOD but now we have more then 28 Bibles we do not know what to do about that where as QURAAN still has the same words since last 1500 years, nothing changed.
Muslim or Christian not doing some good can not be a reason to blame ISLAM OR CHRISTINITY OR GOD OR JESUS OR MOHAMMED (PBUT).

ALCOHOL is prohibited not because SATIN sits in that but it is true and proven by science that when it is taken more them limits (most of the people do take it more them the limits) it harms your body, see driving restriction while under the influence of alcohol. No one can guarantee about the alcoholic person. Most of the times 2 out of 10 persons are sober, when they are under the influence of alcohol. HARAM means that that thing is harmful to human that’s all.
WE also have to realize one thing that the SCIENCE is going to discover more and more, it is in process as we can see that some times scientist say that the theory or the practical of some formula or knowledge has been changed according to new research.
So we do not have to act like one who KNOWS every thing.