Restart your computer to allow the configuration changes to take effect. Plug your Ethernet cable into the back of the Optiplex 790.

Dell provides a tool called for systems running Windows. If you manage to get an internet connection (e.g., via a USB Wi-Fi dongle), you can install SupportAssist. This tool automatically scans your OptiPlex 790, identifies your service tag, and finds all the latest recommended drivers for your specific Windows 7 build. However, for a true "fresh install," the manual methods above are your lifeline.

: Double-click the downloaded .exe file. Click Install and follow the prompts.

Always restart your computer after the installation is complete to finalize the network configuration. Troubleshooting Tips Support for OptiPlex 790 | Drivers & Downloads | Dell US

Right-click on the entry and select Uninstall . Reboot your computer and run the installer file again.

Open the Start Menu, type devmgmt.msc into the search box, and press Enter to open . Expand the Network adapters section.