Cable modem only allows 1 IP address to be used

[Jam]

I was changing settings on my Scientific Atlanta Cable Modem (Telewest/NTL/Virgin Media) to make it allow the wireless router to connect to the DS Lite but somehow ended up screwing it up and now have to use Ethernet for everything, but I think I know its because it will only allow 1 IP address to be used as previously when I used Ethernet I could plug it in to another thing (afterwards, one thing at a time) without having to keep unplugging the modem.

Anyway I can reset it to allow more than 1 IP address (as in .1; .2; .3 and such at the end not entire new IP address) or even factory settings?

Thanks,
James/Jameseh/Mr. Jameseh