Go to C:\Program Files\Adobe\Adobe Photoshop CS5\Scripting in Windows XP or find Photoshop\Scripting folder on your computer for detailed information's.
No Photoshop CS5 and Photoshop Elements are separate programs.
CS5
yes.
Photoshop CS5
Photoshop CS5
Yes, you can upgrade from Photoshop CS3 (or earlier) to Photoshop CS5 Extended, no problem.
cs5 is better
Adobe Photoshop CS5
In Extended version you have 3D Tools to work with 3D Objects.
Adobe photoshop CS5 (extended)
Adobe Photoshop CS5
No. You do not have to have it to upgrade to CS5. CS5 can either be an upgrade if you already own an older version but it is also a fully functional program on its own. if you do not have any versions of Photoshop you would need to buy and install CS5. Then later on if another version comes out you then can upgrade to that version for cheaper.