When I did the first option, run Vizard without Intersense software running, it worked for a while, and then, after working a few minutes earlier, I ran it again and it didn't work. This is the error message:
************************************************** ****************************
* VIZARD 2.51c *
* *
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Loading File: tut_ground.wrl
** ERROR: Failed to connect to intersense
InterSense Library ver. 3.80
Copyright 1998-2003 InterSense Inc.
http://www.intersense.com
Tel: 781-270-0090
Looking for InterSense tracking device number 1.
Please wait
InterSense tracker not present
intersense.dls Intersense Driver v2.0