There is nothing Construct 2 can do to work around popup blockers - they are designed to block popup ads that would irritate the user, and anything C2 could do to circumvent it would be done by ads as well.
Generally the workaround is to only open a window in a user input trigger, such as "on object touched". Browser popup blockers allow popups in user input events, since they are treated as intentional actions by the user.