TweakUi should be one of the first programs to install after the Microsoft Windows XP Setup. It offers a wide range of features, aka tweaks, that override Windows XPs default settings. After installing the freeware you can access it in your start menu in the folder powertoys for windows xp. TweakUi consists of tabs on the left side that expand in the right main window once you click on them. Tabs include Explorer, Mouse, Logon and Templates for instance.
I will give a rough overview of the most prominent features. You can disable those nasty balloon tips and the warn on low disk space message in the taskbar tab. The same tab has a list of all start menu entries which are currently displayed and you can disable the ones that you do not need. The desktop tab lists five usual icons that are placed on the desktop like the trashbin or the internet explorer which can be disabled from that tab.
The My Computer tab makes it possible to disable drives and autoplay from windows xp. You might remember that Sonys rootkit infested music cd installed itself using the autostart feature, definatly recommended to be disabled. Templates shows all New File dialogue options that appear when you right click and select New on your desktop. Remove the uneccessary ones and create new ones.
The logon tab finally gives you the ability to autologon into windows which means that you do not have to enter a password or choose a user from the user selection menu.

Windows stores information about the programs that you use
Windows Explorer File Extension Column
Add Play With Windows Media Player In Windows Explorer
Windows Explorer Menu Editor