Hello, again!

I plan to create a system image backup for every computer (Documents/Pictures/etc are already on the server), so I entered the testing phase with a laptop first, to see if it works as intended. On the laptop I have no redirected folders, so that I may use it at any of the locations we have without needing to be connected to the network. I started using the Windows 7 Backup and Restore utility, and it works like a charm. However, if instead of clicking only the documents and libraries of my user account, I click a system image backup, all bets are off.

Every time I backup the system image, my computer is the only one in the entire domain that can get any access to the network.

Granted, we do have a slow network (100baseT, which I am trying to get the people with the money to change), but it shouldn't shut down all communication with every other machine. So, for you all I have two questions:

1) If this is not working as intended, and isn't just the fault of a slow network, how do I fix it? (Keep in mind, it works fine if I back up everything else, just not if I do a system image.)

2) If it is just a slow network, how do I limit my computer to take up only a certain amount of throughput?

Thanks.