In the folder C:\Documents and Settings\<username>\Local Settings\Application Data\Myst V End of Ages\sav. There is a subfolder for general settings (Startup) and a subfolder for each player (Store1 through Store5).
i've followed your instructions to get to the folder containing the myst folder, but the only folder i see is the microsoft one, what to do???, that means my games are not been saved???
Also, keep in mind that Application Data, as well as many of the folders contained within it, are often hidden. In order to find the folder you're looking for, you'll need to enable viewing of hidden/system folders in My Computer or Windows Explorer by going to Tools -> Folder Options and checking the relevant box in the window that pops up.
---------- Guild of Archivists, D'niPedia Writers Ring (DPWR.NET) Uru and Myst Forum Moderator / Community Assistant Do not PM me for tech support or hint requests for the Myst series