My Sansa clip use to

My Sansa clip use to work, buti plug my sansa clip into ny computer it goes to the menu "San Disk sansa" start up stays on that menu and will not charge. If I do turn it on when it's not pluged and it stil stays on that that start up menu "San Disk sansa" and will keep turnred on til it turns off. My sasa was woring perfectly fine and worked perfectly fine then one day it just stopped, and I tryed every trouble shooting suggestion as well trying to restore my computer back to several differrent times when the sansa was still working when sansa was still working, so the problem is when i plug it into any of my USB ports a message pops up "USB device not recognized" I click on that message and it show all my USB ports and show the on as an "Uknown Devive. I'ver try How can I fix this? PLEASE HELP ME.

Thank you ,
Jon Deel