I have looked for the same thing. Here are some thoughts.
First, right click the volume (e.g., C:) in Windows Explorer and go to Properties > shadow copy components. It's got to be enabled. Also, someone may have pointed it to a different volume.
Second, look at the following web site.
It is an exerpt from a O'Reilly book. Search for "you might be wondering"
It says Shadow Copy is residing in the System Volume Information folder on the designated volume. Read the whole article for more info.
The down side is I looked and still cannot find anything of the size the article suggests.
Good Luck!