Hi Gene,
I've got a BT48 with a spindle. I don't use this machine everyday anymore, when I did it seemed to work pretty good. It now only gets used a couple times per week and EVERY time I want to start things up I get the preview screen, unless I unplug my USB cable from the back of my computer and plug it back in first before trying to start the Shopbot program. I don't have any idea why I need to do this, or even how I figured this out. It seems pretty crazy to me to have to do this. With my previous computer (same machine) I would have to reboot my computer AND unplug/replug the USB cable when I'd get the preview screen at startup.
If I remember right too... when I first started using my new computer (newer than the old one), I couldn't get the front USB ports to work for me and ended up finding one of the ports in back that ultimately worked. I don't know enough about any of this stuff to explain why any of it works, or doesn't work.
My current routine is to turn on the Shopbot control box switch... then unplug/replug the USB cable from the port in the back of the computer... then open the Shopbot software.
I'm sure the smart kids will be along in a few minutes.
Good luck!
Eric Erickson
Shopbot BT48 Buddy