The relevant piece of your httpd.conf should look like this
#
# This should be changed to whatever you set DocumentRoot to.
#
<Directory "C:/wamp/www/">
#
# Possible values for the Options directive are "None", "All",
# or any combination of:
# Indexes Includes FollowSymLinks SymLinksifOwnerMatch ExecCGI MultiViews
#
# Note that "MultiViews" must be named *explicitly* --- "Options All"
# doesn't give it to you.
#
# The Options directive is both complicated and important. Please see
# [
httpd.apache.org]
# for more information.
#
Options Indexes FollowSymLinks
#
# AllowOverride controls what directives may be placed in .htaccess files.
# It can be "All", "None", or any combination of the keywords:
# Options FileInfo AuthConfig Limit
#
AllowOverride all
#
# Controls who can get stuff from this server.
#
# onlineoffline tag - don't remove
Order Deny,Allow
Deny from all
Allow from 127.0.0.1
</Directory>
The important part is the piece after the comment
# onlineoffline tag - don't remove
Wamp manager uses that to find the correct place in the file to change the 3 lines that follow it
When you change wamp to ONLINE that part of the httpd.conf file is chanaged to
# onlineoffline tag - don't remove
Order Allow,Deny
Allow from all
If you have messed with the file it probably cannot find that #onlineoffline tag line
Also if you have put your site into another folder ( other than "C:/wamp/www/" ) as denoted in the <directory> tag it will have no effect on those other directories.