USB-232/4 causes Windows hang when resume from sleep mode

[wantacobra]

I have a problem resuming laptop computer operation following "sleep" or "hibernate" mode. 

With the USB-232/4 connected, the computer does not resume Windows normally.  The display does not return (no backlight or external video output), but the LED indicators (bluetooth, disk, power, etc.) appear normal.  When I remove the USB connection to the USB-232/4, the display immediately returns to the state before sleep mode activated.  Tried all 3 USB ports - all behave the same.  No clues using the event viewer.

Win 7 (64 bit)

NI Serial 3.7, NI VISA 5.0.2, NI-Spy 2.7.2, MAX 4.8

Serial port assignments appear to be correct: 

Port 1 - com15

Port 2 - com9

Port 3 - com16

Port 4 - com8

Any suggestions on next steps to solve this problem?

Thanks in advance.

[wantacobra · Accepted solution]

Solved the problem! 

The BIOS has a setting in the Advanced section for Wake Up Capability.  Enabled USB Wake up from S3.  Now the USB-232/4 is powered during the resume from Sleep mode.  When this feature is disabled, the USB-232/4 did not power up when resuming from Sleep mode and probably hung up the driver, preventing a normal resume.