Navigate to My Computer rught click on the drive and select Properties Tools. Run scandisk and fix any and all errors. Then run Defrag.
Next, if the source of Media Player is a DVD: Carefully wash the disk with warm water with a drop of hand dish washing liwuid. Rinse with copious warm water and dry with a clean, lint-free cloth. If it is fropm a DL file, re-download.
Then reboot and try again.
Tom