I am writing a macro that will take highlighted text, convert any non alpha numeric characters to underscores, and then open a .chm file to the topic named by the resulting string. I can make everything except the regular expression part of that work. I only yesterday started playing with regular expressions, and I'm not sure how to do this, and google was not much help. Here is what I need.... I have, SomeVariable= "?This!String@1#2&3." I need to make SomeVariable= "_this_string_1_2_3_" Here is the set I want to replace [!@#$%^&*()<>{}[]?~`|\/] Is this an easy thing to achieve? Thanks for the help.