"The remote device or resource won't accept.." error, but only at work

Hello and thanks for reading,

I have the oddest problem here at work. I have a brand new Latitude E5530 that would not connect to the internet, but would connect to our LAN. We had the motherboard replaced by Dell, but a few weeks later, while a download of the free AVG anti-virus program was being installed, the same thing happened again where we could not connect to the WAN, but the LAN was fine.

I formatted the HDD, reinstalled the OS (7, Pro, 32bit), installed all the factory drivers and still the same thing.

This only happens when I'm at work. We have multiple laptops of the same make/model/OS that are working perfectly, but not this one (at least not for long)

One thing that does allow me to connect to the WAN. I have a LinkSys USB Ethernet Adapter. There is no Windows 7 driver for this, so I've used the Vista 32 bit driver when installing the software and I can connect no problem.

I've also had one other computer give me fits about accessing the WAN at my job. This unit (I believe it's a Dell optiplex 780) had XP installed and would occasionally lose WAN connection, but a reboot would take care of the problem. The problem grew to where more reboots were necessary until one day nothing could be done to connect to the WAN (once again, the LAN connection was fine). I ended up replacing that computer. Recently however, that computer also was having problems connecting to the WAN, even after removing/reinstalling the NIC driver. I used another of the LinkSys USB ethernet adapters and it has not had a problem in over a month.

I've checked the default gateway, DNS, and DHCP settings doing a ipconfig /all command at the command prompt, and everything matches up. Dell had told me some of the older servers have been having problems with the "New" MAC Addresses, but this doesn't make sense since the Optiplex 780, which is running XP Pro, is an older model and should have no problems.

I'm new to the IT game and would like to have my ducks in a row (or even better, have the problem solved) when I bring this to the big shots. Any help you guys can give would be greatly appreciated.

BTW, first time posting on one of these Tech boards. Thanks for the access and efforts!

Ahh heck! I forgot to add the entire message I'm getting. The error is :

The remote device or resource won't accept the connection.

Sorry for the confusion

Well, it looks like I'll be answering my own question here. It turns out that our DNS server had tons of errors and full logs. A reboot seems to have fixed the situation. Another problem we were having (presumably linked to the DNS issue) is that DHCP was handing out the same IP address to multiple users. We aren't exactly sure why and have a 'static' solution in place and have reserved IP's for these problem computers.

Anyone have any ideas why DNS and DHCP would be having such issues? I don't have any control over these units, having to rely on what the Senior Admin staff tells me so I can't provide details as to what was in the logs, but I'd sure like to have a few rocks in my pocket for our next showdown.