Boosting the Response Time of Start Menu
 

Windows XP Start Menu is pretty slow by default. Changing and editing the Registry Key might help you optimize your Start Menu. The Registry Editor helps you search for, view and edit settings in your system. Before using the Registry Editor, make sure you know how to modify, restore and are familiar with the risks that may affect after changing the settings. If you are ready and aware of the risks, follow these steps carefully:

Navigate to START-RUN, type-in and enter regedit in the text field this should open the registry program. Locate the key HKEY_CURRENT_USER\ControlPanel\Desktop\MenuShowDel ay.
Changing the value from the default value of 400 to a much lower value like 100, 50 or even 0. Another way of improving it is by going to Display Properties Window, go to appearance from there click Advanced command button and check off the Show menu shadow.