do you know any computer law that have been overturned by court and ruled unconstitutional?

Answer 1

Yes.
For example:
In Reno v. ACLU, 521 U.S. 844 the Supreme Court held that Communications Decency Act of 1996 (CDA), that includes "prohibitions [that] embrace all nonprofit entities and individuals posting indecent messages or displaying them on their own computers in the presence of minors"
Was found over-broad and unconstitutional.