from
http://www.computerpoweruser.com/editorial/article.asp?article=articles%2Farchive%2Fc0201%2F49c01%2F49c01.asp

In the Start menu, submenus fade in after a 400-millisecond lag,
which can start to feel like hours to power users. You can make
these submenus snap to attention by going to:

	HKEY_CURRENT_USER\CONTROL PANEL\DESKTOP

and finding the MenuShowDelay value name. The string value for
this value determines the length of the menu delay in milliseconds,
between 0 and 999. We set ours to 1, but you may want to experiment.

Setting the delay too low for your style of mousing seriously slows
down your system, because every single submenu appears when you're
only sliding by on your way somewhere else.

1. Type Windows-R (run window)

2. Type regedit

3. Go to HKEY_CURRENT_USER » CONTROL PANEL » DESKTOP

4. Double-click on MenuShowDelay (I prefer 50)
If this was useful, or you have a question, let me know.   [ more ]