Sure. Regarding the setting of the default Application, I mean the setting of the default App is in Window. Start->Windows setting->Apps->default Apps->Video Player : GOM Player The video files to be opened were downloaded from the internet, ex. youtube etc. The video player “GOM Player” is popular here in Korea. I’ll give you two examples. Search in the Google Search “Cosmic Eye (Original HD Landscape Version)” Linkor here’s a cnn news clip, https://www.bing.com/videos/search?q=cnn+clip&mkt=ko-kr&httpsmsn=1&msnews=1&plvar=0&refig=b989bf7e12424efbaafc0b9fe66b5c5a&ru=%2fsearch%3fq%3dcnn%2bclip%26form%3dEDGNB4%26mkt%3dko-kr%26httpsmsn%3d1%26msnews%3d1%26plvar%3d0%26refig%3db989bf7e12424efbaafc0b9fe66b5c5a&view=detail&mmscn=vwrc&mid=41D29619FD892DBB724741D29619FD892DBB7247&FORM=WRVORC Why don’t you download and open them with GOM Player to test. I am sure you can download the GOM Player with ease. I’ve tried to open one of them with another video player, Windows Media Player, There’s no kaspersky pop up window appearing. That is, no problem.