WT(bleep)? Again, reinstalling drivers form zadig did not help, nor did manually purging the USB devices, oem?.inf files and registry entries, followed by a complete reinstall of the drivers & SDRSharp.
If you have previously allowed Windows to search for and install standard drivers, you may see the devices with other names. Then the drop down menu should show two devices that make up the dongle. Click on 'options' menu and choose 'List all devices'. The only changes to the desktop system were automatic installation of Windows updates. Then execute the driver installer Zadig.exe. Lo & behold, neither would run - essentially the same result as above. For grins, I fired up my backup desktop machine which had an identical SDRSharp install on it (not upgraded) plus a working HDSDR install. OK - maybe I inadvertently trashed something unknown. Running zadig to reinstall driver changes nothing. Yet, the driver is is installed (from zadig) and shows up under control panel. I upgraded to the latest and it now says"RTL-SDR is either not connected or its driver is not working". I had not looked at it for a while (1.5 months, maybe). Remove original libusb driver/zadig directory because Windows might look for all known places to find a device driver. Go to a hidden directory c:windowsinf and delete those oem.inf files which contains a reference to your device. The older version (411) did run, but stuttered. Right click on your device and click Uninstall.
I though I'd upgrade SDRsharp on my netbook (WinXP SP3) to see if newer versions would run a little better. I don't usually do much with the Realtek dongles on win-based systems, and I am less familial with the intricacies of Windows drivers than *nix systems.