You dont need a router however it would be easier if you had one. IF you dont want to get a router you need to clone the MAC address of the NIC in your PC onto your laptop. This is because the STB will only provide access for one MAC address and this has to be register to the STB.
Linksys WRT54GS would be good if your laptop can connect wirelessly
this is a bit convoluted, but in the thread below the person had the same problems except they were using a PS2 and a PC on the STB
http://www.cableforum.co.uk/board/sh...ht=mac+address