Then there is still an issue with IPv6 on your PC that needs to be addressed.
Do you know how to disable it in Win7?
I can't help you with that as I don't have your OS but the IPv6 items I have posted here are:
::1 which is localhost and #Listen [::]:80 which means 0.0.0.0:80
I am also concerned that you don't have the ability to change the IPv4 and IPv6 settings in your setup_xampp.bat file.
Perhaps try this by way of a test to eliminate this issue as you can always enable it again:
http://www.addictivetips.com/windows-ti ... windows-7/
form these Google search results.
Finally if all else fails then uninstall cleanly this instance of XAMPP as per the readme_en.txt file in the xampp folder then either reinstall using the installer version agin or try the zip version and extract manually to the C:\ drive so you end up with C:\xampp then run the setup_xampp.bat file.
After starting Apache and MySQL do the installation check at localhost then try again the LAN and if it fails again then you must have an issue with your LAN configuration.
Good luck and best wishes.