You may get a better response if you post this in the HD/HD+ forum instead of the NC forum.
I have had no problems with Win 8 recognizing my HD+ - my only suggestion is to make sure you have the latest version of Windows Media Player.
Like Swamprat, I've had no difficulty with connecting my HD+ to Win8. I had the original Win8.0 and now have Win8.1, and both are fine.
The Nook HD+ shows up in the file section.
File>This PC>My Nook
And I didn't have to do anything to it.
Have you tried looking under This PC rather than Desktop or Documents?
When you say "not recognized" do you mean in device manager or in Windows Explorer. In Windows Explorer (This PC) the HD+ will not show up as a drive -- it should show up as an MTP device.
Just out of interest, when your Nook is hooked up to your pc, tap the notifications area, and it should tell you whether you have the device connected as a media device or a camera. Tap on the notification to change the connection type. Mine is connected as a media device and is using MTP. The other option is connected as a camera using PTP.
Maybe that is a factor.....