In order to ensure that this ERROR does not persist, start with opening the SDK Manager located in the Android Studio, following which go to Tools > Android > SDK Manager and download Intel x86 Emulator Accelerator with the help of the HAXM installer if not done already. You must next visit your SDK directory which will have the following line of code:-
C:\users\%USERNAME%\AppData\Local\Android\sdk\extras\intel\Hardware_Accelerated_Execution_Manager\ and run the file named intelhaxm-android.exe.
Once this has finished, please restart your Android Studio and then try to start the AVD again which could take upto a minute or 2 to show the emulator window.