You need the Universal Audio Architecture (UAA) Hotfix (KB888111) or the Microsoft Visual C++ Redistributable packages (2010, 2012, 2015). The Realtek installer silently fails without these. Install them first, then retry.
Do not use "driver downloader" tools or third-party sites (e.g., DriverGuide, Softonic, CNET) – they often bundle malware or outdated, incorrect drivers.
If you cannot access the internet on the OptiPlex 790, download the driver on a different computer, save it to a USB flash drive , and then transfer it to your Dell machine.
Use another computer to download the driver if your OptiPlex can't get online.
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