Vista - problems connecting pc and laptop

Good afternoon,
I have a desktop that has virgin internet via a bt phone line. It makes this connection using a speedtouch 330 modem which connects via usb to the desktop. I was wondering if it is possible to connect my laptop to the pc in order to use the pc's internet connection.
I have tried connecting directly using an ethernet cable and it recognises they are connected, i.e i can move files across, etc, and the laptop seems to think it is connected to the internet, however, when i load internet explorer on the laptop, it does not respond. Also, i have tried connecting the two up using a wireless router with an ethernet cable from desktop to router but again the internet connection cannot be made on the laptop.
is there anything i need, or settings that must be changed to allow this (i have allowed the sharing of internet connection on desktop)
Many thanks

---I bought a new (cheap!) router for my laptop also to connect from Main/pc/internet and could NOT make it work; (the store said it could be a DUD) but after million tries - I finally phoned the 1-800-number of router CO. and was helped (yes, in India) very well, step by step to 'configure' the desktop-pc first, then my own laptop after. It all works perfect now! (I thanked that man a zillion times)---

peace