Since you clearly could not understand a Cosmological Argument, I'll try Ontological argument.
First of all, what do I mean by "God"? By definition, God refers to the Creator of Reality. It does not refer to an old man sitting on a cloud. It does not refer to Zeus. It does not refer to Odin nor Krishna nor Vishnu. It refers to THE TRUE CREATOR of Reality.
1) God as we understand Him is a Being than which no greater being can be conceived.
Simple enough. The Greatest Conceivable Being is one capable of Creating all of reality from nothing beside Himself.
2) A Being which exists in reality* is greater than a being which exists only in the mind.
Fundamental vs Secondary
3) Therefore we can't be imagining God.
4) Therefore God exists.