After doing a HP windows recovery (the ntdlr.exe problem from a few posts ago), I noticed something weird: the properties window on C: shows that the ntfs drive is 70GB, but only 2.x Gb is available…

yet, by using utilities like scanner (by Steffen Gerlach), I can see that only 20Gb is in use.

Whats using the remaining 48Gb? How could it be missing?

Well, to eliminate any “behind the scenes” microsoft interference, I start ubcd4win, and I quickly find that the space is in the folder c:userdata

Yet this folder appears empty while xp is running. A quick (actually not so quick… thanks to xp home) change in security settings (and folder ownership) quickly brings the lost disk space back to normal.