Start here:
To enforce file and folder security, boot the computer in Safe Mode and log
in to the built-in Administrator account. Once there, open Windows
Explorer and locate the file/folder you wish to restrict. Right click and
select Properties. Go to the Security tab. Here you can add/remove Users
and Groups, and either grant access to the file/folder, or deny access to
it.
Doug's Security Console
http://www.dougknox.com/xp/utils/xp_securityconsole.htm
Disable or Enable Downloads per User in IE (Line 254) right hand side
http://www.kellys-korner-xp.com/xp_tweaks.htm
Restrict Users from Running Specific Applications
http://www.kellys-korner-xp.com/xp_a.htm#xp_restrict
Use Access Control to Restrict Who Can Use Files
http://www.microsoft.com/windowsxp/pro/using/howto/security/accesscontrol.asp
Add or Remove Programs Restrictions
These restrictions apply to the Add/Remove Programs feature of Control
Panel. They allow you to entirely or individually disable components.
Go to Start/Run/Regedit and navigate to these keys:
Per User
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\
Uninstall
Per System
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\
Uninstall
NoAddRemovePrograms - Disable Add/Remove Programs
NoRemovePage - Disable Change and Remove Programs
NoAddPage - Disable Add Programs
NoWindowsSetupPage - Disable Windows Components Wizard
NoAddFromCDorFloppy - Hide "Add a program from CD-ROM or disk" option
NoAddFromInternet - Hide "Add programs from Microsoft" option
Create a new DWORD value for each restriction required according to the
above. Set the value to equal "1" to enable the restriction or "0" to
disable it.
You may need to restart Windows for the changes to take effect.