My SanDisk clip mp3 won't turn on at all.it only charges when plugged up to a computer

Disconnect the player from the Computer then press and hold the Reset button on it for 30 seconds to reset all the settings to the factory default.

Then, connect the player to a computer to charge it completely. Once the player is charged sufficiently then try turning it ON.

If the MP3 player still doesn't turn ON then the LCD screen is required to be replaced.

Mine was doing the same...not turning on at all not even when plugged into comop. I held the power slide button up for 20 sec, let go then slid it up again and it turned on. Hopefully this works for you its like a reset

Has anyone managed to find a solution to this problem? everytime i connect my sansa to the computer via the power cable or i try charging it using a wall charger, the battery bar doesn't move and neither does the computer recognise the device. i seriously don't know what to do with the mp3 player anymore. i tried restarting it or doing the whole recovery mode thing but both methods were unsuccessful. i spoke to one of the sansa team online and they said that the player is "data corrupted" and that i should purchase a new one. ive been using sansa player for over 2 years now and ive never had this problem before. anyone could suggest anything?

Possibilities include that it's not actually charging properly and is now so very very flat that it can't stay on at all (check your connections, swap your usb port, cable etc). Otherwise, it may be, that the software is corrupt, or that the hardware is physically damaged.
Does it stay turned on when you remove it from the computer connection? If so, take the chance to reformat it (you'll lose whatever's on it now). Plug it back it, and update your software via the sansa updater programme ...
But, if the switch is simply stuffed this won't help!