1. Pci Serial Port Driver For Dell Optiplex 780
2. Dell Optiplex 780 Pci Driver Windows 7

Did you try installing the Wifi driver from the Dell site? Try Windows 10, 8.1, 8 or 7, in that order, or if necessary in Compatibility Mode.

1. OptiPlex 780 – Stability and Management You Can Build On Built on proven technology, the OptiPlex 780 delivers stability you can depend on. Long-range planning support with a targeted 15-month lifecycle, stable images, globally available configurations and managed transitions. Dell Client Manager helps make OptiPlex easy to own.
2. After 3 days of digging, I found the fix for the OptiPlex 790 and 990 PCI Serial Port Driver issue which shows as a yellow triangle under Device Manager. This trouble occurs when you upgrade from Win 7 which is fully-supported by Dell on these machines, to the unsupported Win 8 or Win 10.

Pci Serial Port Driver For Dell Optiplex 780

OptiPlex 780 – Stability and Management You Can Build On Built on proven technology, the OptiPlex 780 delivers stability you can depend on. Long-range planning support with a targeted 15-month lifecycle, stable images, globally available configurations and managed transitions. Dell Client Manager helps make OptiPlex easy to own. Dell optiplex 780 ethernet driver free download - Network:3C905C-TXM Ethernet Adaptor Driver, Network:SiS 900 PCI Fast Ethernet Adap. Driver, Network:3C905C-TXM Ethernet Adaptor Driver, and many. Sep 30, 2019  I have a Dell OptiPlex 780 and I am using Windows 10 Build 14955, every time I troubleshooting: Configure a Device it tells I need to download the driver.

Just because Wifi driver wasn't installed during Upgrade doesn't mean there isn't one. I've never not been able to find a driver. How to: Install and Update drivers in Windows 10 - Microsoft Community

What is always best during OS install is to plug in by ethernet cable to maximize chances it will start up connected or a driver can be found possibly easier. Put the latest LAN drivers in your backup from the PC or Device's Support Downloads webpage so you can get online quickly if it doesn't start up ready to connect.

Dell Optiplex 780 Pci Driver Windows 7

Then type Update in Start Search box, Check for Updates, install all Updates including Recommended, expediting the reboot when requested. Then check again until no more are offered.

Now right click Start button to open Device Manager, import any drivers still missing or in error from the Support Downloads webpage for your PC or the device model. If no Windows 10 drivers, install 8.1, 8 or 7 in that order. Some may need to be installed in Compatibility Mode.