A few things to check if your DTIS display is blank:
1. Please make sure the DTIS application is running. Try and double click on shortcut to DTIS icon. You should get a DTIS icon in your system try when it is running.
2. Please make sure that the monitor is powered on and it is set to the correct input.
3. Please make sure the USB-VGA adapter is properly plugged into the PC's USB port and VGA cable in properly seated into the adapter.