Just an FYI,

Today, I found an issue on my computer.   AutoCAD 2015 would always hangs on startup. The splash screen showed up but AutoCAD just would not start.  All it said was “Loading…” in the lower left hand corner.  In lieu of restarting, I went to the Task Manager and shutdown the acad.exe process.  I restarted AutoCAD and the same thing – Splash Screen hang with the word “Loading…” in the lower left hand corner.

After doing some “googling”, it turns out the InfoCenter process was not successfully closed in previous session.  Usually, this is identifiable the first time you run AutoCAD because Infocenter is being blocked by domain security, firewall or antivirus but in my case it was just a RAW (Random Act of Windows).

See here for more info

In either case, killing the acad.exe process and the WSCommCntr1.exe process resolved the issue!  The next time AutoCAD was started, it successfully loaded.