Just share some experience how I solved this off edge issue. it may not fit your issue.
My system is HP HPE-360z Windows 7 and I decided to use 40'' samsung 1920x1080 TV as monitor sometimes. I connected TV to pc with HDMI cable, then pc dectected the tv and recommand using 1920x1080 resolution. the odd thing is when i select that resolution, like you said, my display is off the edge of screen: i can only partially see the taskbar. If I i lower my resolution to 1770x1000 or 168x1050, i can see the full display.
It so happened that i adjusted the tv display to picture options->size->screen fit, now i got perfect 1920x1080 display on the screen.
hope this can help anyone who got similar issue: this issue is not on pc, it's the tv display set-up.