1
Search online for the make and model of your TV to find its native resolution.
Then right click the Desktop on the TV and select Display Settings.
In there, are you able to set the resolution to the native resolution of your TV?
2
If not, using your TV Remote Control, check the settings on the TV for an AutoFit or Aspect Ratio setting to try to fill the full screen on the TV
3
If you are still unable to resolve the problem.
A
When is the native resolution of your TV.
B
Right click your Start Button and open Device Manager.
Expand the 'Display Adapters' section.
Please provide a screenshot of that full Device Manager window.