My external hardrive isnt showing up on my laptop or my xbox

Hello,
I dont know why but my external hardrive is not showing up, i upgraded to a laptop and am still figuring out mac since ive always had windows. It worked yesterday but now its only making the whirring sound it makes when its plugged in and the little light that usually flashes to let you know its working, has not been doing its job.......
Im worried cause all my kids photos and things for work are on it..... what do i do???