If you like writing scripts you could use Kix32. (www.kixtart.org) You could write pieces of a script to do each of these things that you are trying to do.
If you DON'T like writing scripts then you could use a program like Desktop Authority. IT actually uses KIX in the background but allows you to set everyting up in a GUI.
Changing screen savers can be accomplished by GPO. Installation of software can be done by GPO, SMS, Tivoli etc. You can set up scheduled tasks for restore points and defraging.
If you're asking for technical help, please be sure to include all your system info, including operating system, model number, and any other specifics related to the problem. Also please exercise your best judgment when posting in the forums--revealing personal information such as your e-mail address, telephone number, and address is not recommended.
looking for software to make the same changes to several PCs
basic tasks like:
-changing screen savers
-versions of installed software
-create a restore point for all PCs
-set up an auto defrag at Sunday at 4 am
things like that, I'm not sure if it exists, or where to look.