Website will load forever without http:// in the url, but will load instantly with it included

I have a website that will load when you put in http://my-domain.net but not when you just enter my-domain.net.

I figure this is DNS related, but I'm not sure what to look for in my DNS settings. This behavior also varies from machine to machine. On my PC it will resolve either url, but on my laptop it will not.

Can provide any additional information that could prove useful.