Hi Leah,
Thank you for posting your query in Microsoft Community.
- What is the make and model of the computer?
- What is the make and model of the TV?
Windows chooses the best display settings, including screen resolution, refresh rate, and color, based on your monitor. It's a good idea to set your monitor to the resolution it was designed to display (called the native resolution). To see your monitor's native resolution, check the display settings in PC settings.
- Swipe in from the right edge of the screen, tap Settings, and then tap Change PC settings.
(If you're using a mouse, point to the lower-right corner of the screen, move the mouse pointer up, click Settings, and then click Change PC settings.) 2. Tap or click PC and devices, then tap or click Display. 3. Tap or click the resolution slider and drag it until you find the resolution marked (Recommended). This is your monitor's native resolution—usually the highest resolution your monitor can support. 4. Tap or click Apply.
If the situation remains, you may try the following steps and check.
Step 1: Update the Display driver
Please follow the steps given below to update the display driver.
a. Press Windows key + X key when you are at desktop.
b. Select Device Manager.
c. Find and double-click Display driver from the left panel to uninstall
d. Right-click the device, and click Update Driver Software.
e. Select Search Automatically for Updated Driver Software.
f. Reboot your computer.
Check for the issue, if it still persists go to next method.
Step 2: Visit the computer manufacturer's support website and install the latest display driver available for Windows 8.1
Step 3: You may check with TV manufacturer to see if you need to install any firmware updates for the TV.
Step 4: You may try running the Windows Updates and install all the available updates including the optional driver and firmware updates: Windows Update: Frequently Asked Questions
You may also refer to the article(s):
Get the best display on your monitor
Connect a second monitor or projector
Hope this information is helpful. Please feel free to reply in case you face any other issues with Windows in future.