I have Windows 7. When I hide the task bar it still shows in a bright white 1 or 2 pixel line across the bottom of my screen (as my task bar is on the bottom of my screen). SO if I watch Netflix or Hulu or whatever on full screen (which is a great majority of what I use my computer for) I always have a horrible white line all the time at the bottom of the screen. My computer is attached to my TV via HDMI cable which means that there is not way to adjust the location of the screen image with arrows or whatever. I have read lots of threads and tried many task bar hiding software and none of it gets rid of this problem. It is so awful (no wonder people by expensive Macs). Any suggestions? Thanks!
It isn't quite what you are looking for but... hitting CtrlEsc will completely hide the taskbar. Hitting it again brings it back up. Mousing over it though won't bring it up:
And another solution:
There is also this old application called Taskbar Activate. It does exactly what you want: completely hidden taskbar with mouseover support. But there is an occasional bug where the start button continues to show. The taskbar is always hidden, though.
One more solution with no known "side effects":
Use a theme with a black task bar. That way, the task bar blends in with the screen border, and effectively becomes invisible. It is still there, but you won't notice it (unless you explicitly look for it).
At least Windows 7, and possibly other versions as well, implement the automatically appearing task bar by leaving one or two rows of pixels of the task bar "visible" at the screen border. Windows uses these remaining pixels to make the task bar notice the pointer.
In general, whenever the pointer moves, Windows informs the window under the new pointer position of the event. If the mouse hovers over task bar pixels, the task bar gets notified. This is apparent when another window overlaps these task bar pixels. Then that window receives the notifications, the task bar does not receive any, and does not appear.
In this sense, the fringe pixels are required by Windows to make the task bar reappear. You may make them unnoticeable, but trying to get rid of the pixels altogether would interfere with how the task bar works.