VTS, which stands for Video Title Set, is a name given to video files that are present inside DVDs. These files use the .VOB file format and are encoded with the MPEG-2 standard. Windows Media Player 12, which comes built-in to Windows 7, provides native support for MPEG-2 encoded files so you can play any VTS files that you have without installing third-party codecs.
Click "Start," type "Windows Media Player" (without quotes) into the search box and press the "Enter" key to open Windows Media Player 12.
Press the "Ctrl" and "O" keys simultaneously to launch the "Open" navigation window.
Navigate to the location of the VTS file.
Select the VTS file and click "Open" to play it.