To reset it you can open the modem up and short out switch SW2. I have tested this myself and it works. Afterwards give yourself a static IP of something like 192.168.7.100. You should be able to connect to the web interface at 192.168.7.1 using DSL as the user and DSL as the password.
BTW, there are 4 contacts on SW2. The two you need to short out are the two nearest the edge. You can do so using a paper clip or twist tie.