Really these arguments aren't very good.
There have already been plenty of comments but to touch on to major flaws:
1) The Cosmological argument is just an argument for some sort of "first cause". You'd need to use one of the other arguments to even try to get from there to the existence of God.
2) The version of the Ontological argument starts with a particularly daft assertion. How can "concieve of" be construed so it is actually as difficult as claimed AND we can say that it has been done ? Just thinking up the basic concept is trivially easy (just like it is easy to think of an infinitely long and perfectly straight line).
The latter part of the argument is also daft. At best you can only argue that the CONCEPT must include the idea of actual existence. The conceptual being itself is not any greater if it refers to something that actually exists or less if it refers to something that does not exist.
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