Any tool for organizing my movies (mkv, mp4, srt files) I have lot of downloaded movies on hard drive. Are there any tools (software) for arranging them clearly and in a user friendly way on my Windows PC?
You could use Plex to set up a media library on your device. The interface is as friendly as common streaming services. It also has other features such as support for music, podcasts, and mobile apps.
Setting it up isn't complex but it's a multi-step process so you might want to search and follow an installation guide such as this one
Plex interface (source Plex support page):
Similar to the already mentioned Plex there is also Kodi which has common origins as a media player.
It doesn't require a server and may be slightly easier to set up for local content. It can store metadata about your media files in its own database.
If you don't want a media player and just something to catalog files you can try
EMDB - Erics Movie Database - A movie collection database both for files and physical media
Data Crow - A general purpose collection and catalog database manager that can among other things manage media a movie collections.
Personal Video Database - Specifically for cataloging video and movie files