AutoCAD Architecture :: Project Navigator Continuously Loading?

In my office of about 30 computers and over the course of about 10-12 months we have been experiencing a problem with project navigator. When opening ACAD or changing projects about 60% of the time it gets hung up and the load bar perpetually loads over and over again. If just left to run it takes 5-10 mins to load the project then ACAD will crash after a couple of commands. If opening the task manager and ending the program it will often freeze the computer for about 5-10 mins as well. 

   We have been actively using the project navigator for years and not until the last yr have we been having this problem. We bought pretty much the whole office new computers a few months ago and the problem still exists. We are running AutoCAD Architecture 2012 and our machines are window 7, intel core i7 3.5 GHz, 8 GB ram, 64 bit operating systems, with a Nvidia Quadro 2000 graphics card. So our machines are solid.