There is an IPv6 entry in the Windows host file that Apache can't use which is causing it not to recognize localhost.
Go to
C:\Windows\system32\drivers\etc\Hosts file and open it in your text editor (
in Vista right click on the Notepad link and select to run as administrator which will eliminate an error when trying to save the Hosts file).
Find this line:
::1 localhost Comment it out so it looks like this:
# ::1 localhostMake sure that you now have these 2 lines at the beginning of the uncommented section of your Hosts file:
127.0.0.1 localhost
# ::1 localhostSave the file and then try
http://localhost again.
Kindly let us know if that fixes the localhost issue and if you still have issues with the MySQL not starting.