oke let me try to explain it again..in more easier way.
When UPGRADING windows. -All your current WINDOWS folder stuff(Documents and settings,Program files..etc) will be moved to WINDOWS.OLD folder.
So you WILL NOT loose your stuff that are now located within your current windows installation.
BUT! There is one thing you should know. -Even if your files,programs,games will NOT be deleted(but moved)
You might not be able to play some games or run some programs with your new Windows.