I have an HP desktop model p6206uk. running windows 7 64-bit.
A month or so back, I started to have "no sound" problems. This coincided with a Windows update, but persists even when I fall back to a prior recovery point..
It seems like the Realtek driver is not recognised every time windows starts up or emerges from power-saving.
Initial message was "No audio input device is installed", and sure enough nothing shows in Device Manager.
I have (many times!) updated, reinstalled, and recovered by installing the driver manually, automatically via Windows Update, via Recovery Manager and HP Support Assistant routes. None fix the issue that the driver has vanished again on re-boot or re-power.
Additionally, when I do get the driver recognised, I then run into variations of other Realtek issues, such as "you just plugged/unplugged" and intermittent sound stutters. Advice welcomed!!