I think it's the recovery partition with the information that's needed if you press f12 - recover to factory conditions.
I happened to look at Windows disk management and got a bit of a shock. While my main C Drive partition is considered "healthy" (it's NTFS format) I have two ghost partitions with no drive letters that are also healthy but will not let me know what they actually are. One of them is the "EISA Configuration" partition I've read up on- since my computer is a Dell I assume it's there for the same reason it's there on everyone else's computer (though nobody seems entirely sure, even now, what that reason is.) The loss of 47 unaccounted-for MB in that case isn't a big deal to me, but more perplexing is the OTHER unlabeled partition (called, "unknown partition") that I've found. This one, a FAT32 partition, represents 4.63GB of space- and most of it is filled, with the exception of 682MB- a whopping 86%. That to me is a little more serious, and I'd love to know just WHAT this is- but the only option I get from the right-click menu is "delete partition" and the perfectly useless "help." Does anyone have any idea what this might be, or better yet, no a program that will actually let me look into the drive?