In an earlier comment, it was mentioned that there was a unusually high number of 802.3x pause frames. In the event that this issue occurs again, try your best, if possible to do the following: 1.  Determine the rate of the pause frames.  From the switch CLI, you will just need to refresh the statistics screen every couple seconds and check the difference in count between each refresh.  (exact not needed, just an estimate) 2.  On the switch port connected to the failed server, does the switch see the high number of pause frames on the Rx or Tx side.  (in other words, is the switch receiving pause frames from the server or is the switch sending to the failed server).  The Rx and Tx will show that. 3.  During the outage, if the NIC is flooding your switch with pause frames at a very high rate, there is the possibility that this may cause unwanted congestion on the entire network, just as you experienced.   Unfortunately, the broadcast storm features in that switch will not prevent such outages.  Some of the newer DELL Force10 Switches have a extra storm control feature specific to priority flow control and link level flow control frames.  When this feature is activated, the switch will block offending ports from situations like your (802.3x flooding),thus your network is protected.    Finally, you can even try to disable 802.3x flow control on that switchport connected to the offending server.  This way, if it does BSOD again, there will be no pause frame flooding.  The use of flow control may or may not be needed in your environment so consider that as an option.  
Twice in the last few months we've had two different machines bsod and while in that state, bring down half of our network.  It's somehow flooding the switch, and the switch it's uplinked to, preventing either of them from passing any traffic.  I don't see anything out of the ordinary on wireshark, but I don't really know what I'm looking for.  Spanning Tree and Storm Control failed to make any difference (with their current configuration).  What is causing this and how can I prevent it in the future?
network brought down by crashed pc