You might be tempted to use an online "YouTube to MP4" website. While they seem fast, desktop software is better for Windows 7 because: You can download 10 videos at once.
Websites often cap quality at 720p; desktop apps can go up to 4K.
Visit the official website of the software (e.g., 4KDownload.com or ClipGrab.org).
ClipGrab is an open-source, friendly downloader that has supported Windows 7 for years. It includes a built-in search tool so you don’t even have to open your browser.