Any time I watch anything in fullscreen mode, my taskbar will occasionally pop up, overlapping the video, and dissappear several seconds later, only to come up again. This keeps repeating. This has been happening ever since I installed those 350.12 nvidia drivers (coincidence?). What makes this happen??

Do you have "auto-hide the taskbar" enabled ???

the only things that are enabled:

Lock the Taskbar

use aero peek to preview the desktop

What programs are running in your taskbar ???

...except your clock, your speaker, and your Network connection.

microsoft security essentials

Intel Rapid Storage Technology

Action Center

Nvidia Geforce Experience

What's the video viewer you are using ???

Anyway...right-click on your affected program's executable -> Properties -> Compatibility Tab. Then check the "Disable display scaling on high DPI settings"

Screensavers will sometimes do this. When it comes time for the screensaver to "engage", the taskbar will pop up.

Don't know that it was the nvidia drivers, looks like this has been an ongoing problem for at least 5 years https://www.google.com/search?q=Taskbar+keeps+popping+up+over+fullscreen+video+&ie=utf-8&oe=utf-8. Seems as though each post has found the cause to be something different.

You may want to stay away from the "forum.videolan.org" link, Avast starting giving me warnings on that page, may have been false positives but why take the chance.

It's safe. It is the forums for the http://www.videolan.org/ media player (a popular one, too. I have it).