Ping is a utility used to test connectivity - so when you think you've lost the network connection, ping the device - if it responds, you have a working network connection.
What we are doing here is defining the problem - so, if you can, as you say - a) ping the device, and b) remap it using the ESU, then the network connection IS functional, and the problem is most likely on the Windows side of things - the question now becomes why is Windows (or your application) not communicating over the network - this points back to your security suite, I'd suggest uninstalling it, let's just say, I've seen security suites that continue to block after they have been disabled and I have a personal dislike for Symantec products.