Like I have been saying, it previously worked in a windows 10 clean install without the extra steps.Dell Latitude E6400 Drivers Download for Windows 7,8.1 Category: Dell Laptop Drivers Tags: Dell Drivers For Windows, Dell E6400 Drivers For Windows, Dell Latitude E6400 Drivers, Latitude E6400 Drivers Download.'PCI serial port driver error' points at a Chipset driver. PCI Serial Port And PCI Simple Communications Controller Drivers For Dell Computers 10 Replies After re-installing Microsoft Windows and then downloading and installing drivers on a Dell computer you may notice that you are still left with missing drivers for both a PCI Serial Port and a PCI Simple Communications Controller when you open Device.Similar help and support threads Thread: Forum: PCI Serial Port driver not installed (Windows 7 64-bit) Ever since I installed Windows 7 (64-bit), the Device Manager shows under Other Devices / PCI Serial Port / Properties / 'The drivers for this device are not installed.RE: Optiplex 790 PCI Serial Port Driver Missing after Windows 10 Upgrade One last thought, i do have the driver from windows 7, according to windows, it should work when run in compatibility mode which is what I have been doing. driver Lenovo ThinkPad Helix (37012P6) for Windows 7.Microsoft Uaa Bus Driver for High Definition Audio Driver Win7.