Some background

The internet arrangement in my student home is really weird. There is one ethernet outlet and several wifi hotspots. Either way requires a login through a web site to get internet access. This is annoying as each device needs to login seperately and with a PS3 for example, it is impossible to get connected at all since the web login procedure doesn't work.

Therefore I have installed a D-Link DIR-635 router which is connected to the ethernet outlet. It has DHCP enabled so it uses NAT, but whatever it is connected to also uses NAT and I've read this should not work. A fellow student tried it with an Apple Airport but that keeps giving errors related to NAT after NAT. Anyway my setup does work so bonus points if you can clarify this.

I need to login to the web site I mentioned earlier with any device, after which all devices in my LAN have connectivity. This is great. Except...

In short

From time to time, I lose internet connectivity and my D-Link DIR-635 router needs to do a DHCP renew. I can do this via the web interface but my life would be easier if I could just run a cmd file which tells my router to do this without all the hassle. This would setup a connection to my router and execute the proper command. I have tried googling but couldn't find much helpful stuff.