help me help me

hai i am working in private company , in my company we have 20 client and 1 server.
win2003 server and all client are win xp, i have one doubt , in my office have three section that's accounts, designing and office section,i want restrict particular user enter into any one of client system that allow only particular application. example : office section user enter system 3 that user only use ms-office,excel they not open other application ,next day the same user enter in system 5 that also work only the same application other application must not open .every user have user id and password how to restrict this type help me my buddies.

hope u following active directory architech , this will solve your department problem.

regarding software applications which r installed on local machine , if u want to control by user account all users can have different access and they can control using user rights. each individual machine go to control panel ..>users ...>and define the users access rights for the applications there ..those users can only able to access that applications...when they login as users x , y , z per user rights for x , y , z ...good luck