In order to speed up the Start Menu display in Windows XP, there’s a simple registry setting you can change. Run ‘regedit’ from your command line and look for the following key:
You’ll see a value here for 400, by default. Try changing this to something smaller, like 100 or less. For maximum speed, change it to Zero.
Next, to make things even more efficient, you can turn off the menu shadowing, by going into your Display Properties, click the Appearance tab, click Effects, and then uncheck the option “Show menu shadow”.