Ghost Multicasting Problems 1

[thinkinghard]

Okay, Here's the problem. We have Symantec Ghost 7.0 installed on a PC that acts as a server. We have another pc loaded with Server 2000 and is configured to act as a DHCP server. These two workstations on own a private network. The PC connects to a Cisco 2924 switch. We normally ghost 20 workstations at a time using a ghost boot diskette or cd. This process has worked flawlessly for months however just recently it has stopped working. We have checked everything but now when we try to multicast an image with more than 2 workstations, the network activity slows to a crawl and never completes. In looking at the network activity icon for the PC/Server, the sent packets cease. We've tried new hardware all around. Any help from anyone???