Image via CrunchBaseI've been feeling for a while now that my XP machine is a bit too sluggish - not just in booting up, but also generally opening windows and menus etc. A very quick cure, certainly to speed up your window opening, is to go to the Start Menu and right-click on My Computer. Then open Properties/Advanced, and click the Settings tab in the Performance secton. Normally the Visual Effects are selected to "Let Windows choose...", so change that to "Adjust for best performance" and click "OK".
The side effect of this is to make your desktop look a bit old fashioned, and it will remove any wallpaper, but if you're concerned more about speed of operation, then this easy fix will certainly make a useful difference. I have made this change on 3 computers so far, and have definitely seen an improvement.