I had the same problem, and fixed it by doing this:
- Navigate to https://www.asus.com/us/Networking/PCEAC68/HelpDesk_Download/ and download the driver for Windows 10. (In my case it was Windows 10 64-bit).
- Open Device Manager by holding the Windows key and pressing R. I typed in devmgmt.msc and hit enter.
- Navigate to the yellow warning sign sitting under Network adapters and right-clicked it and selected Update driver.
- Select Browse my computer for driver software and choose the following path from the downloaded driver: [.....\UT_PCE_AC68_v2143\Driver\WIN10] and click Next. (For example, my full path was D:\UT_PCE_AC68_v2143\Driver\WIN10 but yours might easily be C:\Users[user]\Downloads\UT_PCE_AC68_v2143\Driver\WIN10 where your download was saved).
- Windows will install the driver correctly. The internet wasn't working for me right now, so I rebooted.
- Log back in, your internet will hopefully come back on in a few seconds.
(Caveat, you must be connected to the internet over ethernet or save the driver on a separate computer and insert it into your computer with the faulty PCE-AC68 device via usb or cd)
I just tried the solution on clean install of WIndows 10 build 1809 and it did not help: WiFi card is still cannot be installed properly