I got a call that two workstations at check in were off the network. I suggested running Malwarebytes Antimalware. That has fixed a few machines at that account. Note that I just got this account. It has almost 100 devices at two locations, no domain, no centralized anti-virus console, no dhcp, four servers, a Sonicwall, A Cisco Pix, no network documentation. And they are about 1.5 hours from the house in good traffic. Wah. So the local guy ran the anti-malware program which came out clean. He changed out the workgroup switch which did not help. They were attached to a workgroup switch that was attached to a HP Procurve switch. I have found that HP Procurve switches are just about bulletproof. I delay a server install to do what I hoped was a quick look see.
I do my usual delete temp internet files, click box in IE to delete temp IE files when exiting and I delete temp files from user profile. I updated nic drivers. I ran WinsockXPfix which did nothing. I assume that it might do something but they were Windows 2000 boxes. Nothing I could do would get the workstation or my laptop to see the network. I plugged the network cable in directly to a workstation bypassing the workgroup switch and got nothing. I walked back to the HP Procurve switch with my laptop and still get nothing. My $100 cable tester shows 4 blinky lights the whole way so network cable and patch cords are probably ok. I try another port on the Procurve and all was good. The network switch got a stuck port but I was not going to reboot the switch that had 72 devices plugged in to it, especially during working hours. I do not recall ever having a Procurve port get stuck or fail. Plenty of failures on other switches though. Usually a reboot of the switch will fix it but I have had some switches keep failing and a replacement solves that problem.
Back to the check in counter. My laptop works there with the workgroup switch. One of the workstations that was down was now up. The workstation I did the most experimenting with was still down. When I used the same static ip my laptop worked so it was not an ip conflict. I gave up on that troubled workstation and reported back to the company manager. They are on a slow workstation replacement getting rid of these old W2K boxes. As I went back to gather up my laptop and tools I had one last ditch effort. I disabled the workstation nic and re-enabled it. It started working. Man was I in hot water. Those ladies so much wanted to get rid of those old slow W2K boxes.