Roving Network Issues

I just started working with an office a couple times a week, which has a pretty flaky network, it seems. There is a Cisco 2600 providing dhcp (which I have no idea how to work with) and an old NT4 server with shared data for everyone. There are about 50 people on this "network" with about half of them on Macs and the other half on PCs, of all Windows versions from 95 to XP Pro. The first day I got there, we had an XP Laptop that could not access some files on the network, it could see the shared drive, but trying to open files crashed the laptop. I left frustrated, and then the next week, all was well with that one. However, another PC, this one running 2000, was acting up "couldnt print ". Turned out it could not get an P address. No internet, no LAN. The Cisco is locked down and I do not have access to it. All troubleshooting from my end resulted in no connection so I left frustrated again. Came back a couple days later and it worked fine. However, another PC, on another floor, was having troubles. The internet was very slow. However it could release and renew IP, and I could ping the gateway on this one. But, ping showed 25% to 75% loss. I moved the LAN cable from the wall plate by it to a linksys router in the room connected to another wall plate and it worked fine. However, the other PC in the room started acting up: it can see the internet (web pages, etc) and it can print to printers on the network (mapped through TCP/IP) but it can not access the shared drive on the old NT4 server. It says "resource unavailable, you may not have permissions, etc ". This was able to access the LAN just recently. I can ping the gateway, ping other PCs, print, surf the web, but not hit the server. I went to the server and looked at usermanager (no one even authenticates, there is no domain in use) and looked at the shared folders (no limits are set on number of people accessing the share). I applied the latest NT4 patches and rebooted, no change. Rebooted the PC upstairs that cant access the shared folder, no change. We cant remap it, cant browse the network in Network Neighborhood "network unavailable ". Anyone have any ideas as to what is causing this? I bet when I go in next time, this PC will be fine, but another one will not be able to access the network.

 

My first though would be cabling issues. Either the cable itself, the ends, or possibly the wall plates if they use them.

You really need access to the Cisco device too. There are log files on there that can give good diagnostic help.