How does the power of an absolute ruler like the Pharaoh of Ancient Egypt differ from that of a constitutional monarch like Queen Elizabeth of Great Brittan?

An absolute ruler has the ability to create, sign off on, and enforce any rule, law, edict, or judgment that he desires. He is not required to listen to anyone's opinion, though he may solicit it and he is not required to follow any laws himself.

A constitutional monarch is bound by a constitution, restricting his power as concerns his abilities to create, sign off on, and enforce rules, laws, edicts, and judgments. In the case of Queen Elizabeth I, she had no power to create laws and rules and could only issue edicts or sign off on laws or rules given to her by the legislature. Additionally, because the judiciary was a separate branch she had no direct authority over judgments.

The most important difference between a constitutional monarch and an absolute monarch is that the constitutional monarch is bound by the law and can be held accountable for his actions; the absolute monarch is above the law.