I think I've made a big mistake. I followed various guides to setup my MyBook (enabled ssh, changed admin password, installed Optware and Nano). Then I mapped it to a drive letter in Windows and also mapped the MAC-address to an internal IP-address in my router. This all felt like walking on a tightrope but everything seemed to turn out fine.
But then I noticed that it got a new IP-adress on each startup. So I needed the get the same IP each time. I thought that mapping MAC address to IP would be enough be apparently not. So I went to the web interface and "Configure the Network Settings" and for some reason I thought that changing to "Obtain Network Address: Manual" would do the trick. But then I had no idea what the use as Subnet, Gateway and DNS so I left them as they were (blank) and then saved and rebooted.
Now (surprise surprise) I can't access the drive anymore. http://mybookworld/ gives a blank page and Putty can't find it.
You might say that I meddled with things I didn't grasp and you would be correct, but I beg you for advice. Is there some way to revert this and start over? Am I screwed?