Win2k3 clients get this - An active Directory Domain Controller could not be contacted

Hello all;

OK, this is the situation.
I have been running a Win2k3 Server in house for many years, as a Domain Controller.
After moving into our new home, I did not bring the DC back online until the beginning of February. However, the Server Board was bad, so I had to use another system.
Installed Win2k3
And did dcpromo
Set up DNS during that time.
And got it to working.

Now, this is the ISSUE.
NONE, of the computer that are using a Static IP Address, can access the DC
ONLY, the laptop's that have wireless with a Dynamic IP can access and Join the DC.

I have never had this issue before, until now.
I have to have Static IP addresses on my plugged in system's.
The wireless ones, I do not care what they have, just the 4 wired systems need Static Addresses.

I have the preferred DNS server: 192.168.2.7
This is my DC Server's Static Address.

We have a new modem/router as well, from our ISP.
sagemcom 1704n
Not really sure if there is something that needs to be setup in it or not.
That will correct this issue.

This is the error that is received, when you try to join the DC with a Static IP.

An active Directory Domain Controller (AD DC) for the domain "domain name here" could not be contacted.

When you try to ping the server, either by its name or IP address, you get this:

Ping request could not find host server-name. Please check the name and try again.

With a Dynamic IP, everything is perfect.. But I do not want it to be perfect, unless Static Addresses work with it.

It has been a long time since I first installed Win2k3, and made it a DC, that I cannot remember what all I did that first go around, to make everything work.

#1: Is there something that needs to be setup inside of the Router?
#2: Do I need to do anything within DNS, if so, please provide instructions.
#3: Anything that I have forgotten here, please let me know, so I can check it.

Carrzkiss