In order to fix the issue, I recommend you update the drivers of the webcam. Navigate to Asus Drivers and Manuals page, identify your computer model, select your operating platform and download the latest drivers available for your webcam. After that, press Windows + Pause/Break key combination and open Device Manager. Expand the Imaging Devices list, right-click on the webcam driver and select Update Driver Software. Use the Browse option to navigate to the downloaded package, select the driver and install it following the on-screen instructions. If this is not helping, you can use a utility like ManyCam to rotate the output image of the webcam.