I pod the pod comes up with a folder with a warning sign,have press all the buttons ,but nothing seam to work

Have you tried a re-set?
Toggle the hold switch on then off. Then press the center button and the menu button at the same time and hold them down. After a few seconds the screen should flash and the player will re-boot. You may need to try this several times.
If that doesn't work, you may have to do a restore. Connect to your computer and open iTunes and follow the directions for restore. All your music will be erased but you can just re-load it by syncing after the restore is complete.