It could be a number of things but it is probably that apache is Listening on the W8 IPV6 default localhost address which is ::1
1. edit httpd.conf, using the link on the wampserver icon wampserver -> apache -> https.conf
find the line > Listen 80
and change to > listen 0.0.0.0:80
This will force apache to listen on IPV4 and make the pre-configured phpMyAdmin security configuration compatable.
By default phpMyAdmin has the following access restriction:
Deny from all
Allow from 127.0.0.1
IP Address 127.0.0.1 is the IPv4 address for localhost
You may also need to make sure your HOSTS file has the line
or add it if it does not exists.
The hosts file is protected by windows, in order to save it you must have Administrator privilages.
Vista/W7/W8 you may think you are an Administrator BUT YOU ARE NOT.
To successfully save the hosts file do this to launch your editor with Admin Privileges.
Locate your editors icon on the desktop or from the Start menus ( notepad will do if you have nothing else )
left click + shift over your chosen editor icon - will show a menu.
select "Run As Administrator" from the menu.
Navigate your editor to the c:\windows\system32\drivers\etc\hosts file.
When you have made changes you will now be allowed to save them.