I'm not going to read all of the responses here to see if this has already
been answered. I glanced at a few and saw the start of a flame war.
So excuse me if I'm repeating.
The winkey does indeed open the start menu, as you already know. And typing
a letter puts that letter into the search box. BUT.....
If you hit TAB first, it will take you out of the search box and put you in
one of three possible areas of the start menu.
The first area is the right pane of the start menu. The second area is the
one on the lower right with the shutdown options. The third area is the
wider left pane of the start menu.
So it seems to me that 1 and 3 are the areas you want to be in. Once you've
tabbed into the area you want, you can then press the key and it will bring
you to the thing that starts with that letter.
I don't have a pre-Vista version in front of me, but as I recall, pressing a
letter key and having something execute from the start menu worked if there
was only one thing beginning with that letter on the start menu. If, for
example, a program named Pong was the only program in your start menu
starting with P, then pressing P would automatically execute Pong. If
however, you also had something called Poker in your start menu, pressing P
would highlight one of those; pressing P again would highlight the other.
Continuing to press P would simply toggle between the two. To get one of
them to execute, you'd have to hit enter while it was highlighted. That's my
recollection.
Now, I just went back to the Vista start menu to check something and I just
discovered something else: Once you've tabbed outside the search box,
continuing to press a letter will find stuff in BOTH panes that start with
that letter. It will go to the first thing that starts with that letter,
press it again, and it will go to the next, no matter which pane it is in.
So actually, if you press the winkey and then tab and then the letter of
what you want, it should work.
However, it also looks like you have to press ENTER to activate the
highlighted area. Unlike the pre-Vista behavior I explained above, nothing
will activate without pressing ENTER, even if it's the only item in both
panes that starts with the particular letter.