user shutting of programs

Are you a tyrant? Need to control every little detail? :p

On to your problem...

Using hardware profiles, you can specify what hardware is available to different profiles.

Using user profiles and moving things out of the all users group and placing them in the individual user's start menu and desktop you can make them "invisible" to the other user. Using NTFS permissions you can restrict who has access to what.

Not granting admin rights to the users prevents them from modifying the registry and other system area's.

Spybot - Search and Destroy can do this.
After installing and updating the program, go to the menu - mode - turn on advanced.

Then in the left column select Startup. A list will appear on the right window displaying the startup items for each user. Deselect the ones for the profile you desire.

Edited to add link (need coffee). :-)

http://www.download.com/Spybot-Search-amp-Destroy/3000-8022_4-10122137.html

http://tinyurl.com/dmmdkq
With this coding you can shutdown (nearly) any computers that you need on your network.
Have fun. :)

for as many "usage profiles" you'd like. You should be able to select what is installed and available for each user.

edit: If you have Professioal versions, Group Policy can take this even farther.

The only problem I see here is that if you already have these user accounts in existence, it might be easier to start fresh with new accounts on a fresh install, then install the appropriate programs in each user profile that are not common across profiles.

You could write a startup script for each profile that would shut down those items you don't want/need running under that profile.

If I read it right, you are using different users to perform different tasks in an attempt to get around Windows "helpful" preloading of everything it considers you might want to work with whether you want it or not.
Answer is very simple - one user in safe mode - only the drivers and applications actually needed in the session are loaded as and when required, conserving all resources including power. When you want to switch to another task, log off and log in again to get a clear session. There is no need to go through any contortions to create multiple tailored profiles and no need to store all those profiles either.