Configuring a Linksys Wireless router with possible complications from VPN client?

I am having a problem configuring the Linksys wireless router (WRT54G) to work with the cable broadband service/modem provided by Charter Communications (DHCP, not PPPoE or other).  My problem arises after I do the initial set up steps for the wireless router.  Upon setting up the router, either manually or with the CD, I am able to access the internet through both a desktop machine (that is wired to the router) and using a wireless connection via my laptop.  However, once I turn off the computers, I lose the ability to reconnect unless I re-power up the wireless router.  Even then, sometimes connectivity via either wired or wireless is hit or miss.  Also, eliminating the router and connecting directly to the cable modem solves the intermittent connection issue.  I have set up plenty of wireless routers, although usually PPPoE based, never with DHCP...so I have not seen this problem before.  

Through some thinking, I'm wondering if the kink in this setup is the Nortel VPN software (on both computers), obviously DHCP enabled, needed to connect to work.  The wireless router on setup is picking up the MAC address of the Nortel Adapter (the 44-45-53-54-42-00 address)...which I'm guessing means that it is trying to get an IP address through the VPN DHCP?  I'll be honest, I am a novice computer user so anything I have learned about this process has been self-taught.  

Things I have I tried to remedy the situation (if they are dumb attempts to change things, please don't laugh too hard):

1.  Alter/Clone the MAC address to the 00-0F-1F-B7-1E-C3 assigned to my connection.  (Cannot connect to internet.)

2.  Alter the IP address of the router to 198.162.1.200  (Connection to internet, but continues to require a re-start of the wireless router each time a wireless computer is powered up.)

3. Disable the Local DHCP routing on the wireless router.  (Cannot even connect to the router anymore, much less get to the internet.)

I have also been reading about the problems between wireless routers and VPN connectivity, so I am anticipating that problem will also arise, but first off, I need to get my wireless router working.  

I saw a post on another site that recommended using port settings.  
http://www.velocityreviews.com/forums/t298913-vpn-connection-problem-with-wireless-router-in-network.html
Would this fix my problem?

I have also read about the problems with competing security any trying to disable WEP/WPA, but that seems to be more related to VPN connection issues.  I will try that, but not sure it will help in my situation.  

Below I have included my ipconfig info.  Any help you can provide would be greatly appreciated.  I do know another person who has this problem with the same wireless router, same broadband provider, and same Nortel VPN client.  They can only access the internet when they are connected through VPN, otherwise, they have no internet connection.

Thoughts?  Please let me know what more information you need.  Thanks!


Windows IP Configuration

        Host Name . . . . . . . . . . . . : ***
        Primary Dns Suffix  . . . . . . . :
        Node Type . . . . . . . . . . . . : Mixed
        IP Routing Enabled. . . . . . . . : No
        WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Local Area Connection:

        Connection-specific DNS Suffix  . :
        Description . . . . . . . . . . . : Broadcom 570x Gigabit Integrated Controller
        Physical Address. . . . . . . . . : 00-0F-1F-B7-1E-C3
        Dhcp Enabled. . . . . . . . . . . : Yes
        Autoconfiguration Enabled . . . . : Yes
        IP Address. . . . . . . . . . . . : 192.168.1.100
        Subnet Mask . . . . . . . . . . . : 255.255.255.0
        Default Gateway . . . . . . . . . : 192.168.1.1
        DHCP Server . . . . . . . . . . . : 192.168.1.1
        DNS Servers . . . . . . . . . . . : 192.168.1.1
        Lease Obtained. . . . . . . . . . : Sunday, December 23, 2007 1:56:00 PM

        Lease Expires . . . . . . . . . . : Tuesday, December 25, 2007 1:56:00 PM

Ethernet adapter {F1A68334-5241-4F98-AF6E-EA4633F26E84}:

        Connection-specific DNS Suffix  . :
        Description . . . . . . . . . . . : Nortel IPSECSHM Adapter - Packet Scheduler Miniport
        Physical Address. . . . . . . . . : 44-45-53-54-42-00
        Dhcp Enabled. . . . . . . . . . . : Yes
        Autoconfiguration Enabled . . . . : No
        IP Address. . . . . . . . . . . . : 0.0.0.0
        Subnet Mask . . . . . . . . . . . : 0.0.0.0
        Default Gateway . . . . . . . . . :
        DHCP Server . . . . . . . . . . . : 255.255.255.255