Quite curious to know if your Wifi works (properly) as well?
That is, when you connect your NUC to the net does it maintain a stable connection (by that I mean, remaining connected and the speeds you get remain constant / consistent)?
That and, what driver did you install? There are two setup files for the 7260AC (one is just the driver, the other which comes bundled with the ProWireless software).
I ask as I too have issues with this card. Haven't tried the WiDi setup yet, but my Wifi is sporatic at best. Will be uninstalling and reinstalling the alternative driver tonight and will update (installed the ProWireless variant of the driver). And to note, I have a W7 x64 setup on my D54250WYKH
I tried the software with included drivers and with the drivers only too, but as I said, the problem is always there.
My wifi connection is okay and I have no problem with it, but the bluetooth is another thing, because I use a bluetooth mouse and the pointer stops at random times for 5-10-20 seconds, but I will open a new discussion for that problem and keep this only for the WiDi issue.
Tried the driver-only 17.0.3 and that didn't work. After quite a bit of time researching I read that driver versions 17.0.0 work fine (and these come with WiDi drivers too, like the 17.0.3).
And that seems to have fixed my wifi issues. Not curretly home with my NUC so unable to try out WiDi anytime soon. But maybe you could try using the 17.0.0 driver as well. Just make sure you uninstall the previous driver THEN restart / reboot the machine before installing the new (17.0.0) driver. Will minimize risks of random driver conflicts.
I installed the ProWireless version of 17.0.0 (not the driver-only setup).
EDIT - Not yet properly played around with bluetooth yet; here's hoping that doesn't cause a headache like the Wifi drivers did...