Follow-up...

The Google Chat application turned out to be the process that was "hogging" the webcam for me. The DirectShow diagnostic tool (dxdiag) referenced in this thread led me to this. Upon reviewing the output (way down toward the bottom) I could see a reference to this application. Google Chat has an integrated video capability that was grabbing the webcam during the computer startup.

The summary of logging and diagnostic info/tools (attached in this thread) was very helpful - Thanks Scott!