Actually, the driver's (file) name is indeed vwifimp.sys, and that Windows did automatically reinstall the adapter; except that it took time before the adapter could be "used" again.
I mean, yesterday I executed "netsh wlan show hostednetwork", but the "Hosted network status" was "Not available" instead of either "Not started" or "Started".
Also, when I went to Device Manager -> "Network adapters", and viewed the "Microsoft Hosted Network Virtual Adapter Properties", the "Device status" was:
Currently, this hardware device is not connected to the computer. (Code 45)
To fix this problem, reconnect this hardware device to the computer.
But now, the status is back to "This device is working properly .". Yay!
So problem solved and lessons learned!