I don't see how the virtual NICs would block the actual NIC. You should just be able to disable them.
What are you pinging? IP, computer name, FQDN?
If you want the answer fast and Sandeep isn't around, just go to
www.experts-exchange.com. You can get a 30-day trial. If you ask the question and choose the following topic areas:
OS --> VMWare
DNS
Misc Networking
you will likely get answers within 20 minutes
Also, can you post your server and the bad computers' ipconfig /all
