Xpy is a great little freeware application that lets you change windows xp settings with ease. The normal way of changing items would be to use a registry editor, search for the relevant key and change the value of that key. Xpy aids you by offering options to change many settings with a simple click of the mouse button.
A great feature of xpy is that it is able to check the settings of similar tools like xp-antispy and display them in xpy. You can control the settings of both tools without the fear to disable a feature you changed already. The open source software xpy allows you to make changes to seven different categories like services, usability and delete files.
Some of the most useful changes are the following:
General: Disable Error Reporting, Disable Remote Assistance, Enable Fast Shutdown
Services: Disable Automatic Windows Updates, Disable Messenger Service, Disable Firewall / Connection Sharing
Windows Messenger: Remove Messenger from Outlook, Uninstall Windows Messenger
Usability: Disable Balloon Tips, Disable Thumbnail Caching,

Change Security Settings with Safe XP
Define Default Windows Vista Folder Settings
WinGuggle change Vista performance settings and OEM information