How much troubleshooting have you done in the way of checking XAMPP/WAMP? For instance, have you simply uninstalled the server to see if it restored your internet connection? Or have you tried disabling the server services in XAMPP/WAMP to see if that made any difference? Or did this really require a full OS reinstall?
While it would be odd for this to be true of the default settings, it could be how you have the server configured that could be conflicting/interfering with your PC's internet connection.
There's also fancy command line stuff you can do like 'netstat' to try and see exactly what is going on with your internet connection. You'll need someone else to go into more detail on something like this as I'm not familiar with it.