i went to add more songs on my 8gb player but it said file not found-now when i plug into my computer it says 2.5gb left but no songs or files are found on the computer or my device?

Likely. MTP-MSC USB mode issue:

The Clips have 2 USB modes, MSC and MTP.  (There also is a third, “Auto”–player tries to use MTP mode but falls back to MSC mode, if necessary.)  Set under the player’s System settings. 

When connected to your computer, the computer only sees the files on the player that were transferred to the player under the USB mode that you then are connected to your computer under.  And so if files were put on the player when the player was set to MSC USB mode and the player is now set to MTP mode, the computer won’t see the files.  Or if the player is set to Auto USB mode and the player has changed between the MTP and MSC modes behind the scenes, you can have the same result.

To avoid:  set the player to either MSC mode (recommended; it’s the simplest, under which the player simply is seen as a drive) or MTP mode (needed to play protected files) and leave it there; avoid the Auto mode.  And to “correct” what’s already been done:  set the player to “the other” USB mode; connect to your computer; transfer the files you see on your player to the computer; delete those files on the player; disconnect the player and set the USB mode to your “new” mode; connect to your comouter; and transfer the files back to the player.  Now all your files are under one USB mode, the one you’re going to stay set to.