localhost doesn't work but 127.0.0.1 does?

[nickphipps]

http://localhost/
will not find my server which is running, however it is available via the apache ip 127.0.0.1 or by my network ip

I got an error notice on my xampp index page telling me my site cert is expired and when checking it out, sure enough, it's almost a year out of date.

Is there a way of fixing this problem? Do I have an old xampp version installed and therefore an old apache setup?