XPS720,
I would try this:
1) Make note of the comm port # of the ProScan instance communicating with the 536 and the instance communicating with the 200. To get the comm port #, go to the Comm Port menu then see what the port is set to.
What is the 536 port set to? ______
What is the 200 port set to? ______
2) Go into the Device Manager and make a screen shot of the Ports section or at least note the Ports assignments like in this image.
3) Put the computer into sleep.
4) Wake up the computer.
5) Go back into the Device Manager and compare the Ports with the ports from step 2
Advise on your findings.
See if the SDS200 still beeps and does a reboot.