AutoCAD Inventor :: Display Randomly Freezes And Won't Refresh

Anyway, I just updated to the Factory Design Suite Advanced package for 2011 which, of course, includes Inventor.  I have downloaded and installed all updates, service packs and hotfixes I could find btw.  What happens is I'll be working in Inventor on a solid model of ANY size (even a single part) and with absolutely no warning, the display window will freeze up and won't refresh.  What's really weird though is that Inventor itself is not locked up.  I can click on any of the buttons or any of the items shown in the browser as though the program's running normally.  I can check the task manager and it shows Inventor to be running normally.  The memory status bar in Inventor shows lots of available memory.  I can even hover over the display window in the area where the view steering wheel is located and the icon will change appearance as though it's working normally.  I can even save the file.  If I close the file, it responds like normal and goes back to the default screen.  If I try to open ANY file after that, however, the screen will not refresh or show me the file I opened, even though everything else works fine and the program isn't frozen.  The only way to restore full function is to completely close and reopen Inventor (on average I have to do this about once an hour).  Btw, I'm also working in a local directory stored on my hard drive, not a network.

My first inkling is that it's a graphics issue but I have played with all the display settings to no avail.  I ran a diagnostic on the video card and Inventor says that I'm running an Autodesk Certified driver.  All the specs are within reason I think.

My workstation specs:

Dell Precision M4500 laptop

Intel core i7 processor, 2.67 GHz

4 GB RAM

Windows XP Professional SP3, 32-bit, running in 3 GB mode

NVIDIA Quadro FX 1800M, 1 GB graphics card (just updated the driver too...no change)

230 GB hard drive, 136 GB free space