On some Windows systems (especially Win7), there have been cases where the serial port driver cannot be installed.
Here is the solution:
Step 1:
Install Virtual COM Port Driver
Link:Virtual COM Port Driver V1.5.0.zip
Step 2:
Right-click "My Computer" to enter Device Manager.
Right-click the DOREMiDi device with "!" and click "Update Driver Software", as shown in the figure:
Step 3: Select "Browse my computer for driver software", as shown in the figure:
Step 4:
Select "Choose from a list of device drivers on your computer", as shown in the figure:
Step 5:
Select "Port (COM and LPT)", as shown in the figure:
Step 6:
Select "STM..." and "STM...Virtual COM Port"
If the pop-up box warns, click "Yes" to continue the installation, as shown in the figure:
Step 7:
Wait for the installation to succeed, as shown in the figure: