Good luck B

Hi. Using MP4 files from a video camera, the file is visible in the first preview (?) window, but when dragged to the Timeline the image is black (audio track shows). Nothing will play. The blue loading bar hasn't moved in 50 mins for a 3 minute clip... This is a new computer to me. Have previously used VideoPad for a few years without any problems. Suggestions most welcome! Should I uninstall and try again? Thank you!