Hey guang,
The examples are located in C:\Program Files\IVI\Drivers\niScope\Examples\VisualBasic. If you do not have these, download and install the newest ni-Scope driver (2.7) from the website and look again.
look here for newest driver:
http://digital.ni.com/softlib.nsf/webcategories/85256410006C055586256BE600709528?opendocument&node=132060_US
Good luck with your application.
Sincerely,
Gavin Goodrich
Applications Engineer
National Instruments