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4 computers named C1, C2, C3, C4 (ALL WINXP SP3) with IP addresses assigned by router DHCP
1 workgroup named OFFICE

My OFFICE workgroup shows following computers:

C1, C2, C3, C4, NAS and

Here is the fun part.

C4 and seem to be one and same computer. They have same IP address: but different computer names. Both computers point to same C4 computer and its shared folders and windows seems to be fine with that as there was no IP address conflict error. On the other hand, I do get occasional My Network and Show my workgroup hang ups and/or long delays.

I have never created a computer named with the name same as its IP address. It just suddenly showed up in the OFFICE workgroup. There is no fifth computer in the network; just C1-C4 and NAS.

Looking for an answer, I found a suggestion to change workgroup name to erase unwanted computers from the workgroup, so I tried that. I changed the workgroup name, hoping that way I will get rid of the phantom computer with an IP address as its name, but as soon I changed the workgroup name back to OFFICE it appeared again.

Most of other searches produced answers that are dealing with IP addressing problems (lookup, same IP address two computers etc.) I could not find anything on a computer that has a name same as its IP address, that showed up for no apparent reason.

Any idea how to erase the IP-named computer? It would be great if someone can explain how/why it appeared in the first place. Could it be that I somehow have two DHCP servers active? I checked the DSL router and NAS and router is the only one assigning addresses.

UPDATE: Feb 15, 2013.

I tried to rename the C4 computer to I was expecting an error because of the duplicate name. Instead I got an error message that says I can't have a dot in computer name and a computer name cannot be all numbers. So how is it possible that all of a sudden I have a computer in my workgroup that is named

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This normally happens when Windows has saved multiple credentials of the same computer with multiple names, namely it seems it has saved C4 and it's address as two different cconnections (and therefore, credentials).

You can go into windows credentials manager and remove it.

Hope that helps.

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Thanks for swift reply! Tried that. No credentials saved. Nothing to remove. – user198039 Feb 13 '13 at 21:41
Hm, I am looking into it now, but to quote MS tech support: "The problem may also arise due to some old network adapter settings– a. Click onStart menu, type in “devmgmt.msc” to open the Device Manager. b. Click on View and choose Show Hidden devices. c.Now scroll down to Network Adapters and right click to uninstall those that are showing with transparent icons. If nothing is grayed out, then your problem is also not with an old network adapter. d. Restart if you have uninstalled any old network adapter and then check if the issue persists." – Alastor Feb 13 '13 at 21:46

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