Copying an entire drive onto a folder on another drive

It is further alleged that on or about Tue, 25 Apr 2006 00:42:52 GMT, in alt.computer, the queezy keyboard of "Bazzer Smith"

Using XP I tried this, I copied all the files by opening the drive (lets call it drive d:) and grabbing every thing in d:and dragging it to a folder on the main drive. However I noticed the sized of the drive and the folder I copied it to were different (the one in folder was smaller) Then I tried doing it a different way by clicking on the drive (without opening it) and selecting copy. This seemed to produce a folder of the same size. I am guessing the second method copied some 'low lever' (invisible data)? (Or I screwed up the first time I tried it?). Anyway buttuminig I didn't screw up which is the best method? Bascially I want to copy all the data off the drive to free all the space and then use the drive to put other data on (so I can use it to transfer that data elsewhere) and then when I have finished I want to restore the drive back to its original state by copying the original data back onto it. I am now of the impression that the first method was best, either that

or I don't know what I am talking about :O) -- -nos1eep