I have my widi working fine with Windows 8 pro (latest hd4000, wifi, widi drivers and software).
I had the same initial issue of unstable connection, keep asking for security code etc. Before Windows 8 everything was working fine with Windows 7.
I installed the Windows 7 wifi/widi drivers and software Under Windows 8, it detected a version 2.0 of the firmware of my Netgear PVT2000 and offered to update it to a 3.1.29. Then I installed the latest wifi/widi drivers released for Windows 8 and it could connect to the Netgear and ask again to update to the firmware 3.5.28 (if I well remember). Since everything is working like a charm. It seems the latest Windows 8 widi cannot connect to too old firmware and then ask to upgrade. That would answer some issues I have seen on this forum (was not able to reply directly to their question).
HOWEVER, if I connect through remote desktop to the same computer, when I start widi, it claims the configuration is not compatible with widi.
I even connected my widi locally before connecting through Windows 8 remote desktop, it then disconnect the widi and display that the configuration of the sound has changed. I disabled the sound card of the additional graphic card I have which was not used for connecting the widi before using remote desktop client but it says now that it has a problem to display the desktop on the second screen without claiming any issue with the hardware configuration.
I ran the automatic detection of the drivers before and during the remote desktop, intel returns the same configuration and the same comment up to date.
I tried a different remote desktop software than the Microsoft Embedded one (teamviewer) and it works fine. It seems there is a defect in Windows 8 pro remote desktop which without changing the configuration seen by the remote desktop, break something used by widi to establish the connection. Since it is working with another remote desktop software, I am not sure between Intel or Microsoft who can make a fix.
Can intel drive the fix and patch widi or ask its Partner Microsoft to patch Windows 8?
NB: the versions I used to do the intermediary patch of the firmware were the last version for windows 7:
Wireless_15.3.1_s64 pro/set full driver+software (around 79Mb)
then the latest version for windows 8:
I kept the graphic hd 4000 updated by windows 8 for both widi installation: 126.96.36.19967