Cannot Access Router With External Network Adapters

I am running Windows 7 Home Premium (64 bit) on a Dell Inspiron 560. I am using a DI-524 D-Link wireless router. I have an Acer Aspire One Net Book running Windows XP Home it is equipped with an internal wireless network adapter. I can connect/communicate with router and access the internet with no problems whatever. However, when I connect an external wireless network adapter e.g. Alpha AWUS036H I cannot get a connection when I disable my internal network adapter. I have also tried the Trendnet TEW-424UB USB external wireless network adapter and the symptoms are exactly the same.

If I leave home and use another Wireless point of access I have no trouble connecting using the external adapters which means the problem is confined to my personal home network.

I have removed and reinstalled my router, and the network adapters drivers etc. I have uninstalled my Norton Firewall and and disabled my Windows firewall to no avail. I have removed my WEP security features and tried to run it open with no improvement. I have connected the external network adapters on a neighbours computer running XP to see if I could connect to my home network. That didn't work as well.

Bottom line is I simply cannot get an external wireless network adapter to work with my router. Yet my internal netbook adapter connects with no problems at all.

Any ideas?

The following is a copy of my ipconfig file, as you can see only IPv4 is being used:
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.

C:\Users\Roger-Jeanne>ipconfig /all

Windows IP Configuration

Host Name . . . . . . . . . . . . : Dell-PC
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : hsd1.ca.comcast.net.

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . : hsd1.ca.comcast.net.
Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller
Physical Address. . . . . . . . . : B8-AC-6F-D9-46-E8
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IPv4 Address. . . . . . . . . . . : 192.168.0.100(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Lease Obtained. . . . . . . . . . : Tuesday, May 31, 2011 6:43:49 AM
Lease Expires . . . . . . . . . . : Tuesday, June 07, 2011 6:43:49 AM
Default Gateway . . . . . . . . . : 192.168.0.1
DHCP Server . . . . . . . . . . . : 192.168.0.1
DNS Servers . . . . . . . . . . . : 68.87.76.182
68.87.78.134
NetBIOS over Tcpip. . . . . . . . : Enabled