here is an addition:

To keep your windows xp running at better speeds there are some visual styles that you can disable to make your speed increase. Certain things like slide menus into view and show windows content while dragging are really just stupid effects that dont matter.

To turn off and on visual styles right click the my computer icon then select properties in the drop down list. a window will apear select the advanced tab then clcik settings underneath the performance section. Once you clcik the settings button a new window will apear there will be three tabs at the top if you are not already in it then select the visual effects tab. There are 4 options there they are 'let windows decide what's best for my computer', 'best appearance', best performance, and customize. the first 2 options are the same thing and are exactly how your windows should look when you install it. the third option runs your computer in classic mode which looks like the older version of windows. So like it says if you want best performance you should like that but if you still want to keep some xp style on your computer then you should customize.
here is a list of effects that are unnecessary (all effects are unnecessary but you wont like the look without some of them):
Animate windows when minimizing and maximizing
fade or slide menus into view
fade or slide tooltips into view
fade out menu items after clicking
show window's content while dragging

if you want even better performance out of your windows xp you should run it in 16 bit color this is a good idea if you have a bad graphics card or low system memory. to do this you just have to right click on the desktop then select properties. a window should apear select the settings tab then click on the drop down box and select medium 16 bit color. I also find that it is easier to run things in a 1024 by 768 screen resolution.