Would you mind explaining you reason for wanting it? Any programs on the task bar are one click starts and any program can be pinned to the taskbar. If you hit winkey + 1, the first program from the left will start, 2 the second and so on.
As far as your question, I do not know for sure, but maybe there is a window's process that goes through the registry or somewhere and corrects what it thinks are errors.
I am aware of the pinning feature of W7. However I dislike it for several reasons.
Firstly, it takes much more room compared to quicklaunch, and there is no difference in opening the file, not faster, or anything. The only special thing you see from pinning taskbar opening is you see it "expand". Not much difference. For emphasis, I have attached an image for comparison between quicklaunch and pinning.
Secondly, I got used to the pinning feature of Win XP.
Thirldy, I am having this PC shared with my parents, who barely knows how to use the Start menu. Yes indeed it's a click/search away, but they said it was too complicated to access skype via start bar. Don't ask me why, they say they like it at quick launch and keep asking me to fix up this quicklaunch dissappearing bug.
In reply to your quotation
" If you hit winkey + 1, the first program from the left will start, 2 the second and so on."
I am interested - what feature are you talking about? I pressed the Window Key and 1 together doesn't open me anything...
Also, the regedit gave me a BLACK screen. So don't try it.
It's in the root HKEY SOFTWARE > MS > WINDOW NT > WINLOGIN and something in there....
I think the file was userinit