Well, well, well.....very interesting, indeed!  And enlightening!  I am glad to have a name of the disease, so to speak. 

I downloaded (what I think is) an even newer driver - 257.21 - from NVIDIA, and now that I think about it, I haven't had the TDR happening since then.  Although, I may not have used the computer to the upper end since then either.  But I am hopeful... Thanks a bunch for letting me know.  Here is the link to the newest driver:

http://www.nvidia.com/object/win7-winvista-64bit-257.21-whql-driver.html