3801HGV residential gateway hard wired ethernet connection issues

I have had U-verse for about six months to a year now.  I first had issues with my home network where none of my laptops wanted to see my desktop (Windows XP SP3).  I finally figured out it was the Mcafee firewall and shut it down resolving that issue.  I was able to track down the issue when my desktop started losing connection despite indicating it was connected to the network.  Shutting down the Mcafee firewall fixed this too for about two weeks.  It started with every three to four days I would have to reboot my computer to connect to the internet.  I could access the gateway but nothing else.  Today that stopped working and I had to reboot the gateway early this morning.  By 1700 nothing was resolving the problem when it came back.  I tried rebooting the computer, gateway, and changing cables with no luck.  The TV still worked but nothing else hardwired.  I checked with another desktop I had which is running Vista Home and same problem but it wouldn't even detect the gateway and its worked fine in the past (No Macafee either).  Last but not least I plugged up my trusty dell laptop (Windows XP) which has a wirless connection and plugged in a hard wire and it detected the connection but was unable to successfully link on some occassions and on others would show linked but again no internet.  So I called up the ATT customer service and they recommended another reboot of the gateway.  Now after this reboot I couldn't get many channels with uverse TV they came in as black only.  I rebooted the gateway again and it got worse.  Finally I rebooted the cable box and got my channels back.

So in summary the following hard wire LAN or Ethernet connections are dead

1. IBM desktop running XP SP3 (Either can't negotiate connection or shows connected but no internet)

2. Dell desktop running vista (shows as cable disconnected.)

3. Dell laptop running XP SP3  (Either can't negotiate connection or shows connected but no internet)

I have another router which I connected the laptop and IBM desktop to and they connected fine with it but they refuse to connect to the 3801HGV.  I currently have the desktop running off wireless which is functional but not the same as a good hard wired connection. 

Things I have tried.

1.  Shutting down all firewalls (nothing)

2.  Rebooting gateway (nothing got worse)

3.  Rebooting computer (nothing)

4.  Changing cables (nothing)

5.  Updating LAN drivers (nothing)

6.  Tested cables with another router (tested good)

7.  Tested computers with another router (tested good)

Can anyone think of what else might be the problem as this one has me a bit frustrated.  I didn't wire my house for LAN for nothing..........or apparently I did.