In his first post he says "If I look at the C drive in My Computer I see 14 GB free, 41.5 GB used."
That would imply the stats he quotes are from one 54.5 gig partition. A quick look at Disk Manager should show if there's any factory restore partitions or crap like that though.

I'm upping the odds on the System Volume Information folder from "long shot" to "distinct possibility".
On my home PC, it shows as 0 until I add in permissions for the logged in user - then it shows 15 gig (old restore points, etc).