Cannot get internet access on any PC connecting to DIR-615 router when I connect it to DSL 320T Modem

I have connected my D-link Wireless N DIR-615 router to my D-link Ethernet DSL-320T ADSL 2+ Modem. I have done this my attaching an RJ45 ethernet cable in the 'ethernet' socket on the modem and have then attached the other end of the cable in the 'Internet' WAN socket on the Wireless router. I have used this configuration, so that the router can share the internet connection over my network.

I should also state that whilst I have only just purchased the router, I have been using the modem to recieve the internet successfully for over 6 months. It has worked fine by either attaching it directly to a PC, or plugging it into an Apple Wireless Access Point (AirportExpress). In addition, the router seems to work fine when I access it either wirelessly or by ethernet cable. So far, I have had no problem accessing or changing the router's settings.

My problem is that, when I attach the modem to the router, I am unable to receive the internet on any PC that connects to the router (either wirelessly or by cable). However, the 'status' tab on the router web configuration shows that the router seems to be working in conjunction with the modem. This is given that the 'WAN' status is displaying a public IP address. In addition, the 'Internet Connection' icon in the 'network connections' in Windows XP states that the PC is 'connected' to the internet. However, I have tried this on 4 PC's with XP, and they all have the same problem, ie. the router and XP are showing that the internet is 'connected' but I am unable to surf the web or receive email.

The problem I am suffering is after following the D-link instructions that are specifically intended for connecting the D-link DIR-615 router to  D-link Ethernet DSL-320T modem:

http://www.dlink.co.uk/?go=gNTyP9CnptFMIC4AStFCF834mptYIe1STtvhLPG3yV3oU4B8gKltbNlwaaRp5zwlED2onGQTo4kEFN3h3aTnKE0WuO0=

Here are the settings under the 'status' tab of my DIR-615 router:

WAN
Connection Type : DHCP Client
Cable Status : Connected
Network Status : Established
Connection Up Time : 0 Days, 0:01:58
MAC Address : 00:1B:24:1F:54:E6
IP Address : VALID PUBLIC IP ADDRESS
Subnet Mask : 255.255.255.255
Default Gateway : 192.168.1.1
Primary DNS Server : VALID PRIMARY DNS
Secondary DNS Server : 0.0.0.0

LAN
MAC Address : 00:1C:F0:5F:2C:15
IP Address : 192.168.0.1
Subnet Mask : 255.255.255.0
DHCP Server : Enabled

Other necessary information:
The above router status is based on setting the internet connection type in the router to 'Dynamic IP (DCHP)' and I have also put my ISP settings into the modem. I have not set the internet connection type to PPPoE on my router and entered my ISP's username and password directly into the router, as I have tried this and it did not work. However, as mentioned above, all the equipment shows that the internet is 'connected' when I put the ISP settings into the modem and enable 'Dynamic IP (DCHP)' on the router. Incidentally, the 'internet on' light on the router is lit up green constantly.

As far as both products are concerned, I have repeated the setup process a number of times, and have performed a factory reset before each attempt. I have also connected the modem to the router using the standard procedure of 1. plugging both out, 2. plugging the modem back in and 3. attaching the modem to the router when the ADSL light on the modem turns solid green. I have tried changing the modem's DCHP settings to 'do not assign DCHP to any attached devices' but this has not worked either.


Given that all my PC's are suffering the same problem, this would seem to suggest that this is something to do with the router, or possibly the settings on the modem. My current internet provision is by Pipex, and I have contacted them to confirm that I am using the correct settings  everything is fine. The internet connection itself is through the phone line and is an ADSL line and is a PPPoE connection with a dynamically assigned IP.

Are there any settings that I need to change on my router, or even my modem?

I should also add that I have already contacted support on the telephone, but they were not able to assist me any further with the situation above.


Product pages:

D-link DIR-615 Router
http://www.dlink.co.uk/?go=gNTyP9CgrdFOIC4AStFCF834mptYKO9ZTdvhLPG3yV3oWIh2gqltbNlwaaFp6DQoHDrpyyFA+Y8BA9jj

D-linkADSL 2+ DSL-320T Modem
http://www.dlink.co.uk/?go=gNTyP9CgrdFOIC4AStFCF834mptYKO9ZTdvhLPG3yV3oVo5+h6ltbNlwaaFp6DQoHDrpziVF9o0OBN/l


Thanks a lot