Hello there myu98198!: go to whatever company which made your HD (such as www.hgst.com , www.seagate.com
or www.westerndigital.com )as examples & it might behoove you to also download diagnostic software that this manufacturer offers as well just in case something else is also behind this disappearance
once downloaded & installed all you have to do is follow what you see on your monitor
good luck
hope this helps & enlightens you
spacechild