FVG318v2 network outage when Win7 system turned on

[teamx]

I have a very strange issue that I'm hoping that someone has run into.
I have a FVG318v2 that is working fine with all my XP systems. I just got a new Windows 7 desktop and Windows 7 laptop when I power them on and connect them to the network either cable or wireless the Windows 7 system will have internet access but all my other systems will loose their network connectivity. This will even cause local LAN issue when the Win7 systems are on. What should I be looking into???

[adit]

What brand/models of computers?

Any common applications on both PC's?

NIC manufacturers?

[teamx]

I have one new Lenovo laptop using wireless and one Dell desktop both only have office and Anti Virus software on them. As soon as them come up the XP systems are all disconnected.

[adit]

What is running DHCP on the LAN? DNS?

Does one or the other cause the issue? Can you isolate it to one of them?

NIC drivers up to date?

Do the XP devices lose their IP addresses?

Can the XP devices ping each other?

Can the XP's resolve a hostname at the command prompt?

[teamx]

What is running DHCP on the LAN? DNS?
DHCP is running along with DNS
IPV4
IPV6 was running on the Win7 boxes but I disabled it seeing how its not being used.

Does one or the other cause the issue? Can you isolate it to one of them?
Both Win7 systems cause the same issue.

NIC drivers up to date?
Yes

Do the XP devices lose their IP addresses?
No they still have a leased address but can not resolve names and local communication is also lost.
Connections to the server from the XP systems are terminated.

Can the XP devices ping each other?
No

Can the XP's resolve a hostname at the command prompt?
No

[adit]

But what is running DNS and DHCP?

You mention a server but not what it was.

Is the XP disconnect immediate, or does it happen over time?

What is the physical layout of the LAN?

[teamx]

But what is running DNS and DHCP?
My FVG318 is configured to be my DHCP Server and also has my DNS entries.
My client systems are all running DHCP

You mention a server but not what it was.
My server is Windows 2003 also running DHCP

Is the XP disconnect immediate, or does it happen over time?
Yes XP clients are disconnected immediately

What is the physical layout of the LAN?
ISP connection comes into the FVG318
FVG318 feeds a NetGear 24 port switch
The switch feeds the client ports

[adit]

You can only have one DHCP server on a LAN. I suggest you use the server for both DHCP and DNS, disable DHCP on the router.

Disable DNS Proxy on the router.