To billko - I appreciate that, thanks!
To all - yes, the code wasn't "clean and proper" but I wasn't going to create VI's or sub VI's until I had code that worked properly. It's just my personal style, but when it's a relatively small program I prefer to debug it by laying it all out flat, placing probes along the way, and then running it. When I have good, solid code, I go back and clean things up with subroutines and sub VI's.
And I finally got it working!!! I wrote a short program that opened up a VISA session on the COM port, did a flush and CLR (redundant, but wanted to be sure!), and then closed the session. That's all it did. I ran that program one time on the Win 7 computer, and after that my code worked fine! Just for fun I even tried all my different versions of code (I had eight of them!), and every single one worked. Even after rebooting the pc, and plugging and unplugging all the other devices, it still worked. Wheewwww....
Apparently somewhere along the way the COM port buffer was full or corrupted or something was not letting go of the COM port in the background.
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Amateur programmer for over 10 years!
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