Hi, good day! I'm John Dev a Windows user like you and I'll be happy to assist you today. I know this has been difficult for you, rest assured, I'm going to do my best to help you.
Please try to open and use Microsoft Clipchamp
Sign-in on the app > Create a new video
Import your MP4 File then drag the MP4 video onto the timeline at the bottom.
Click on the clip and drag the edges inward to trim the video.
Click Export in the top right corner, choose the resolution, and save your trimmed MP4 video.
Kindly let me know if this helps or if you have any further concerns by clicking the "Reply" button at the end of my response. I will appreciate it.
Kind regards,
John DeV
Independent Advisor