DNS head-scratcher...

Hi everybody! First time poster, here. I've frequented this particular forum on a few occasions, and I have gotten quite a bit of good information and help! I hope I can return those favors someday!

Anyway... I have a 2K3 server in my domain. I have roughly twenty-five Windows7 workstations, some 64-bit, some 32-bit, but all Professional. I have half-dozen XP Pro workstations still in the enterprise, they'll be phased out soon enough. I have one Ubuntu workstation.

I can ping the Ubuntu workstation by host name and IP address. In the DNS, there is no PTR, but there is an active DHCP lease.

I can ping SOME of the Win7 *and* XP workstations (by either IP or name), and the ones I cannot ping are completely random.

Example:
W7-64 Workstation "deanna ". IP address xxx.xx.x.120
Seen in DNS - PTR record exists.
DHCP lease exists.
tracert fails to resolve.
Cannot ping, either by IP or name.
Will not answer when queried by PandaAdmin Console, thus cannot install AV software.

W7-32 Workstation "kelley ". IP address xxx.xx.x.129
NOT Seen in DNS - PTR record DOES NOT exist.
DHCP lease DOES NOT exist.
tracert fails to resolve.
Cannot ping, either by IP or name.
Answers when queried by PandaAdmin Console, and installs AV software.

Both of these workstations are plugged into adjacent ports on the Cisco 50 port switch, and physically located in the same office. There are NO special setting in the switch software for ANY workstation. Cisco Router is NOT doing anything but firewall and NAT, with port fowarding implemented for four servers inside the network.

Additionally... Once I started installing the W7 workstations (properly removing the XP boxes that they replaced from the domain, of course) every XP workstation that still lives inside the network will pop me an error:

"A duplicate name exists on the network "

This is strange to me, as well... When I removed the old XP boxes, I didn't even return the same workstation name to the W7 boxes as I implementned them!

PLEASE help! It's driving me insane, and I have about a dozen workstations with no antivirus installed! These girls have NO concept of the dangers in clicking "sure, why the heck not" to every popup they see while browsing!

Any suggestions will be explored, or if I've already checked into it, I'll tell ya!

I do know that I have not been able to find anything relating to A records... This keeps rearing its ugly head while trying to locate the resolution to this issue. Maybe that's got something to do with it? If so, how do I determine WHERE the A records are, and if they are not there, how do I *put 'em there "...?