I use a Mac not a PC so unsure what your problem is but I have found this which may help
Click on the "Start" button in the Windows Taskbar, at the lower left of your screen.
Click "Default Programs" and the Default Programs Control Panel will open. This is where you can control which application launches automatically when you open a particular type of file.
Click "Associate a file type or protocol with a program." This opens a list of file types. Find the file type you want to disassociate from the VLC player. For example, if you don't want ".mp3" to open with VLC, click on that file type.
Click "Change Program." A list of currently installed programs will open. Pick the program you want to be the default for the selected file type. For example, you might choose Windows Media Player for .mp3 files. You must choose an alternative program or VLC will remain the default player.
Click "OK." Verify the change has occurred by double-clicking any file of the type that you modified. The file should open automatically in the application you just assigned.
Repeat steps three through five for each file type that you want to disassociate VLC from.