Question : How do I identify the source of continuous errors on a network?

Hi everyone,
I have a network at work and has been giving me a lot of headaches because every now and then the entire network is down (except for my server which is running Windows 2003, which makes me assume it is not an ISP problem but rather an internal problem). Here is a breakdown of the problem:
1- When I started working I found a wireless router (Cnet) configured to act as a dhcp server whilst the server (Lan and Internet configured on the same server, it has multiple NIC's) itself was also configured to do so as well

2- There are multiple IP addresses on the authorization list, lets say 1.2.3.4 is LAN address, 5.6.7.8 is the internet address, and there two more addresses which I don't know what they refer to (I found a chaotic situation since nothing has been documented, so I pretty much have to guess a lot of things).

Up until thursday, everything  was working fine,  but since yesterday the network is down and I can only surf the net directly from the server or if I connect directly to a port in a switch which is fed directly by the server but the problem comes when I try to surf by connecting to other switches (connected via a cascaded mode), these same switches are the ones supposed to distribute the signal to the different access points throughout the building. I have even changed the switches but still. The other issue is that everytime there is no internet, I cannot even log on to my Lan (is this a configuration problem?)... Hope I am making sense with my explanation!

Any help will be greatly apreciated.

Rgs

Answer : How do I identify the source of continuous errors on a network?

Good to hear about your status. If you can narrow down the problem is from one switch, you can easily sort out the bad apple could be apples. I still don't understand how your Antivirus server did not detect the bad one. You may have to make visit on every computer on that switch to make sure Symantec has been up to date. As you know I am in the industry for a while, I have seen that situation before (I am serious!). This network plan had been created years ago before the virus or worms invented. Anyway, I understand that you are in a transition and there is no clear network diagram in place. It is hard but you have to start getting one. You can see it's never too late. You can get a network probe tool to trace your cables
http://www.allspectrum.com/store/product_info.php?products_id=1116
http://store.cablesplususa.com/kp100.html

K

K