Networking Problem on Windows XP

[Vertigo]

Right now I have a small mixed network setup at my apartment, 2 laptops using wireless then my PCs all connected to the router. There are currently 4 PCs connected to afore mentioned router, all but one of those PCs is able to see the others. The one that I am posting from right now doesn't show up in the newtwork places, even though it's set to the same network name, etc. I look in my list of computers on the network and Animus does NOT show up. Though obviously it IS getting internet. I'm not able to get to any files I'm sharing, etc. Which is really a pain because there are some rather large video files I was trying to move around so I could edit them on this box. Coincidentally this machine doesn't see any of the other PCs either. Any ideas? I thought it might be a virus or something. So I ran AVG, RogueScanFix, Adaware, Spybot S&D, and nothing. Also tried turning off my firewall to see if it might be blocking things, and still nothing. Any and all help would be greatly appreciated.

P.S. I've noted a possibly related issue. I can't certain software now, I just tried to install Microsoft Net Framework for another program I was about to put on, and it gave me an error before I was finished installing. I tried installing from the exact same location (the microsoft website) on a different machine and it works fine.

[crenn]

Type in the computer name into the address bar and see if it connects.

e.g. \\ANIMUS

What firewall are you running?

[Vertigo]

Nope, it won't connect to it by typing the name in the address bar, I'm just using the default Windows firewall.

[nevermind1534]

What about typing its ip address after the \\

[Luke122]

Is the IP in the same subnet as the other machines?

Are all the computers members of the same domain or workgroup?

Is the IP hardcoded on the un-working PC? Try setting it to DHCP instead.

Check router settings to make sure that the one PC address isnt set in the DMZ.

[AMD Killa]

dont forget simple file sharing (or in vista, password protected sharing). Other than that, disconnect your internet from your router. Then turn off all the firewalls, then test it.

[nevermind1534]

Some routers have firewalls with an option to not let computers on the network connect to each other.

[crenn]

Some routers have firewalls with an option to not let computers on the network connect to each other.
This doesn't seem to be the case this time. If that was the case, none of the computers could connect to each other.

[nevermind1534]

True.

[AMD Killa]

Are you using patch cables? As in 4 pairs rather than 2?

Also, how old is the NIC for computer that can't see the others? It might not support full-duplex communication. Also, you should make sure you have the latest drivers for it.

[Vertigo]

I have updated drivers on the system, it's my main rig that was built less than a year ago, it's Animus in my signature.

EVGA 132-CK-NF78-A1 LGA 775 NVIDIA nForce 780i SLI ATX Intel Motherboard that's the mobo in question. Everything is hooked up to a Netgear Wireless router using normal Cat5 cable. Everything is in one room, so I don't see a need to go all wireless on my gaming system. When I first built the system, it was seeing the other computers, etc just fine. Then one day it stopped, and hasn't since. It's odd, because I play WoW on it daily, browse websites, etc. It IS connected to the internet, just for some reason it's acting like a ghost on my network. I had a laptop that did this at one time, but it was a Dell laptop and I found out it was a security feature in it's Firewall from McAffee, problem is I don't have a firewall that I've installed. Only the Windows Firewall that comes with XP, and it's currently shut off.

[crenn]

Can it connect to any other machines?

[Vertigo]

It doesn't see anything else on the network, and nothing else on the network sees it. If I go to Network places on the afflicted computer and look at other network computers, I see only it. And it is likewise excluded when doing the same on any other computer on the network. I verified by setting a new network that they share the network name, etc. And still nothing. I'm about ... this close || to doing a full drive wipe and reinstall of Windows, I'm sure it'll fix it but since I can't drag and drop files to other computers I'm leary of losing some data.

[AMD Killa]

How many computers do you have networked together?

You should consider making a server - client network instead of a p2p network if there are more than 3 pc's. That way, it's all centrally managed on a low-cost low powered server machine (possibly made from old recycled hardware) to handle file sharing, security, internet access, and even roaming profiles.

Try booting a linux live-CD to the problematic PC, and see if you can see the other computers then. If not, it might not be a problem with the machine.

[SgtM]

Something really simple that I didn't see mentioned yet. Make sure it's in the same workgroup.

[Crazy Buddhist]

When I first built the system, it was seeing the other computers, etc just fine. Then one day it stopped, and hasn't since.

This could be due to a number of issues.

As others have mentioned the workgroup name has to be identical on all machines. I'm sure you have this covered.

The fact that it was working one day then stopped implies possibly some kind of malware that is interfering with/snooping your network traffic but you have done the scans so if it is this it's a deeply embedded rootkit.

There are known problems when using mixed variants of windows on the same network. If this is the case one of the known solutions is to give each of the machines on the network a fixed IP addresses (in the routers range) rather than DHCP assigned ones from the router. You set the IP address, subnet mask and DNS servers for the machines in network connections --> connectionX --> TCP/IP Properties. Requires a reboot on some windows after resetting to fixed values.

Another possibility is to check the networking components bound to the network adapter you are using on this one machine. Open network connections, right click on the connection and chose properties. Confirm you have the following clients and protocols bound to that adapter as you will need them all for filesharing to function:

"Client for Microsoft Networks"
"Service Advertising Protocol"
"File and Printer Sharing for Microsoft Networks"
"NWLink NetBIOS"
"Internet Protocol (TCP/IP)"

There may be others - don't worry about them. If all of the above are present then:

Click on "Internet Protocol (TCP/IP)" -->
Click on "properties" -->
Click on "advanced properties" -->
Click on the "WINS" tab -->

Ensure "Enable NetBIOS over TCP/IP" is checked. Click OK all the way back down. It may ask you to reboot.

NetBIOS over TCP/IP is the protocol that windows file and printer sharing uses for exchanging packets to find resources on the network. In a workgroup the computers negotiate amongst themselves which machine will keep track of what is where.

If any of those clients/services or protocols are missing (NWLink NetBIOS especially) there is your problem. Click on install. Find the missing component and install it. Reboot if needs be, then go back to TCP/IP properties and ensure "Enable NetBIOS over TCP/IP" is checked.

Giving all the machines on the network a permanent rather than DHCP assigned IP address would be the next thing I would try if this has not resolved it.

CrazyB

[Vertigo]

Well, I think I've found the solution.

I'm reinstalling windows. Infact, I've decided to wipe all of the machines and start fresh, 2 having had a fresh OS install in over a year. So, I'm going to make my own boot up disk of XP with the SP files and all on it then do my install, meanwhile I just got a new 500g external drive. I'll backup on it, time for a bit of a fall cleaning of the PCs. As for the server, I was planning on putting one together with an eMachines PC I recently aquired. It'll have to sit on the backburner for a little bit while I get all of this situated. I figure in a week, I should have this whole thing nixed. I honestly think it's a bit of malware, I just can't seem to locate it. So, as stated above, it's probably a deeply embedded rootkit, it's not the hardware, I tried using an Ubuntu distro and it worked just fine, I thought about using this method to move my files, then reformat individually. BUT ... if it really is an infection I'd rather purge it entirely than risk spreading the infection to the rest of the computers. Thanks a lot everyone for your advice, I'll post back after I get this situated.

[SgtM]

Use dban (http://dban.sourceforge.net) to wipe them.

[Vertigo]

Thanks Sarge, I'll check that out.