I currently have a clients server that every so often experiences a condition where it stops responding to network requests.
You can still ping the server, and it still processes some basic commands, like a shutdown command, but it does not allow browsing files or folders, and you cannot RDP to the server. You will also be unable to launch applications if you manage to logon to the server locally.
You may have experienced a similar condition after regaining access to the server you will most likely see that the System log is full of Errors. In my experience this will be Event ID 2019, Source, SRV.
The Server was unable to allocate from the system Nonpaged pool because the pool was empty.
I have seen this occur on Servers and Workstations, there are a lot of fixes suggested online, but so far Read more of this post