Hello again.
Firstly, Rob.
Yes, the modem to router connection is definitely going into the single 'internet' port at the back, I have that done fine.
I tried what you suggested, releasing and then resetting the DHCP in the router's settings, but it appears to make no difference.
Gareth (nice picture, BTW), I don't know how to find what IP I am getting on the PC, I did try searching for how to find it, but I am not quite sure what you meant, sorry