DNS Problem on windows 2008 Server

If the machines are Vista, go to the network and sharing center and make sure that the networks are listed as private.  If they are public, you will not be able to see past the firewall.

All the workstations on the domain are windows XP Professional SP2 or SP3

Can you ping an outside address by IP address?  Try to connect to http://64.233.161.104/ (google) and see if it connects.  Also if you run ipconfig /all does it show a dns server?

2 of the machines are unable to ping outside the firewall the other 8 are able to pring outside the firewall
if I run ipconfig /all I get IP address SN, gateway, DNS servers, shows the dhcp server., I can even use programs on the server I just cannot get outside the firewall on these 2 machines. one of the machines is a fresh install of windows XP

First check that the gateway address is correct (address of the firewall).  You might try to put in a static address on the machine (IP address, gateway and dns servers) and see if that helps.  Also check the firewall is not blocking those addresses by either IP or by MAC address.

Gateway is correct, it is the firewall. Static address doesnt help. The firewall is not blocking IP or MAC adddress

Find the MAC address of the firewall from one of the working machines (arp -a <ip of firewall>) and make sure the other 2 machines are using the same MAC address.

the results of arp -a  192.168.1.1 00-90-7f-1c-e9-e1 on working machine and 2 non working machines

I'm starting to think the issue might be at the firewall.  From the filrewall can you ping the machines in question?  Have you rebooted the firewall to flush any bad arp cache or bad routes?

I can ping the machines in question from the firewall. The firewall has been rebooted. Remember I have 8 other machines that connect and browse without problem..

Had another thought.  Have you installed a third party firewall software, usually included with the antivirus software?  If so try disabling it, along with the windows firewall to see if it is blocking access.

I have windows firewall turned off, I have removed the anti-virus. I even reloaded the OS on one of the machines. II am beginning to think there is something wrong with the NIC.  The only thing that makes me think it is nit the NIC is that I get assigned IP address, SN Gateway, DNS1 & 2, and I can browse the Domain and use applications I just cannot browse to the outisde of the firewall and If I bring the machine home with me it accesses the internet no problem

run route print and make sure that the 0.0.0.0 network is pointing to the gateway through the right interface.  
You can connect to internal machines - not likely the cable or the nic
If your firewall has the capability, try to log all packets and see if any packets are getting there from the machine in question.  It might also give you a clue why they are not getting through.

You can try changing out the nic just incase it is something really wierd.

I am sure you have tried this, but have you tried using a different IP address?

Solved the problem.  Was a combinations of several things you suggested and I had already tried
7pm last night I systematically rebooted all the devices in the rack. I was getting some positive responses from the 2 machines in question. I so decided to turn everying off and let it sit for 30 minutes. I brought everything down the switches the routers, the servers the firewall everything. the rack sat  without power for 30 minutes then I systematically brouht the rack back online and the 2 machines in question worked. Thanks for your help.. sometime you need another head to bounce ideas off of. Thanks again i will be awarding you full points

Thanks for your Help..