If it is in Windows and your PCI serial port driver stops working, there is probably a yellow mark in the Device Manager as in the image shown above, you are not alone. Many Windows users are reporting it. But the good news is that you can fix it.

If your PCI serial port driver is in the other devices list or if it is missing, or if you want to download a new PCI serial port driver, these are the two options for you. Choose the one you prefer.

Update the PCI serial port driver through the Device Manager

1) On your keyboard, press the Windows logo key and R at the same time to invoke the Execute box.

2) Type devmgmt.msc in the box and press Enter to open the Device Manager.

3) Right-click on PCI serial port in the other devices section. Then click on Update driver software...

4) Click automatically searches for updated driver software.

Then, if Windows detects the updates, the PCI serial port driver will be updated automatically.

5) Restart the computer and verify if the PCI serial port driver works.

Note: For some reasons, Microsoft may not detect the update of its driver. If the driver still does not work, continue with Option 2.