Restarted Computer, Black Screen, Checking for Inconsistencies?

My computer started acting kind of funky so I restarted it then all of a sudden windows wouldn't load but a black screen came up that said some of the disks are inconsistent and then it went through this whole MS-DOS looking thing, kind of like a scan. And now my computer restarted. What did that mean? That I have a virus or is my hardrive failing? Thanks.