ARP.exe error and network slowing down. Related?

treysha

I am running a NT 4.0 server with about 50 clients. Clients are on Win 98, XP, ME and OS X.
Recently, the network seems to slow down a lot, both the LAN as well as the Internet.
I looked at the network switches and saw A LOT of broadcasts (meaning ALL the lights on ALL the ports blink simutaneously).
Also, I get this error msg a lot on my server:
"ARP.EXE Entry Point Not Found
The procedure entry point SnmpSvcGetEnterpriseOID could not be located in the dynamic link library snmpapi.dll"

I ran searches on the net but found that most of the time the error occurs when something new was installed but I could swear I hadn't installed anything new.
I called my ISP to ask about the internet slowness, they told me that it is possible that there is a "massive" infection of some kind in my LAN.

Does the error msg have anything to do with the network slowdown?
And how do I identify which workstation is "massively infected"?
Can anyone give me any advise, please?

kryyst

Well for starters are you running any anti-virus software? And if not you seriously should be. As for checking if you have a router or your server is routing traffic you should be able to check the routers or the servers event logs to see which ip is generating the traffic that will narrow down your search. The other thing you can do and this is a very manual process. But just go through in a day in order, unplug one for a minute and see if the switches settle down. Then unplug another and check etc...etc...