How do I fix a distorted or garbled display on my external monitor connected to my laptop?

Adjust the resolution of your laptop display to the optimum resolution that matches the output of your external monitor.
Turn off your laptop, disconnect the external monitor, and then restart your computer.
Check the physical connection between the external monitor and the laptop.
a. Make sure that the cable is properly connected and that it is firmly secured.
b. Check if the cable is in good condition or if there are any signs of damage.
Check your laptop's System Settings for the Display options.
a. Look for the Multiple Displays option.
b. Go to the control panel and look at the available display options.
Adjust the Refresh Intervals for your monitor.
a. On most monitors, you can find the Refresh Intervals by right-clicking on the desktop.
b. Select the Refresh rate option and increase the value to match the refresh rate of the external monitor.
Update the video card driver for your laptop.
a. Go to the Device Manager and update the video card driver.