All of a sudden our internet at work became very very slow, pretty much not working.
Called the isp and they could not ping our router. Disconnected our network from the router, then they could ping it. They said we must have a machine on the network slowing down the internet. Removed all machines one at a time till we found the problem, which turned out to be the domain controller. It's running Win 2003 SBS, Exchange 2003. Rebooted, did a lavasoft adaware se scan and virus scan, not sure what is causing the problem.
What should I do from here?