Sounds like the database has become corrupt. The only cure for this is to restore the player.
This can be caused by shock to the player, not "safely disconnecting" from the PC, or incompatible Windows or Media Player version.
Assuming you player is a Philips HDD1830, install and run the Philips Device Manager from the product CD.
Select the repair/restore option.
Connect the player to the power supply and PC, then follow the on-screen prompts.
This will format the player, and restore the system files.
NOTE: ALL TRACKS WILL BE DELETED.
If you player is an SA6085 or SA6185, then the same method applies, but you will need to press and hold [VOL+] on the player whilst connecting to the PC, until told to let go.
If this doesn't help,, post your model number for more specific help.
on Jan 04, 2014