If God is all-powerful, can He create a rock so big that He can't lift it?
No. God cannot do the logically impossible, any more than He can act out of character with Himself. God cannot, for instance, create a square circle, stop being good, or cease being God. God can do everything that is possible to do, which includes those acts for which there may be no simple, immediate, apparent, human explanation, i.e. miracles. For further study, see Jeremiah 32:17, Matthew 19:26, Hebrews 6:18, and 2 Timothy 2:13.