The documents and settings/user
/start menu/ folder is the start menu for that user.
The general start menu shared by all users is documents and settings/all users
The way to control start menus is not to use Windows Explorer to delete startups but rather the msconfig utility which unless you know what you are doing can create serious problems.
If you feel you must adjust startup items use Startup Inspector
instead. It will at least give you an idea of what a program is if you click on it on the right side if its screen.
And Startup Monitor which you can get on the same page will nitify you if any aps try to load themselves into the start menu and require your approval in a popup screen.http://www.windowsstartup.com/download.php