WD My Passport 500GB External doesn't show up

I have a similar problem. I have a Western Digital My Passport 500GB External and one day it just up and didn't load files. I've had problems with my ports so I've tried them all. After a few tries it did not show up on My Computer, so I went to Device Manager and again it did not show up. I plugged it in on my old XP computer and it came up unformated. So under Computer Management-Disk Management I tried reformatting it. In the end it said could not reformat, an error of some kind. Any new suggestions/help is greatly appreciated.