Good morning everyone!

I've recently reinstalled a clean windows 7 on my computer. I have a folder with all my works. I use to be able to recognize all my works created years ago thanks to the thumbnails that were created long ago in explorer. The folder looked dirty but at least I was used to it and could recognize more less easily each of my videos (there's about a hundred of hem in the folder). But since the new installation, the thumbnails have all changed and about a third of the thumbnails are black, because somehow, on 30% of the videos, the frame used for thumbnail is from the very first seconds of the video.

Now I have another folder with jpeg pictures assigned to each video to use as thumbnails on youtube.

So is there a reliable software that I can use for the windows explorer of windows 7 sp1 to replace the newly chosen frames by any jpeg file I want?