To reopen a document you've already saved and named, you can pursue any of these avenues:
Open your My Documents folder (or whichever folder contains the saved file). Double-click the file's icon.
If you've opened the document recently, choose its name from the Start→My Recent Documents menu. (If you don't see this command, simply install it as described in Section 1.15.)
If you're already in the program that created the document, choose File→Open—or check the bottom of the File menu. Many programs add a list of recently opened files to the File menu, so that you can choose its name to re-open it.
Type (or browse for) the document's path and name into the Start→Run box or into a folder window's Address toolbar.