how to use SED to replace comments within a comments section

Assume that I have a file that starts with the following /********************************************************* blah blah blah blah blah blah blah blah blah *********************************************************/ Actual code follows here code code code The command I used: sed -i 's/(/*).*(*/)/\1 newcomment \2/1' file but I received the error message sed: -e expression #1, char 14: unknown option to `s' p.s. my question is ... how can i REPLACE the "blah blah blah..." comments with other bloah bloah bloah comments ?