C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Startup

For startup items only for a specific user, the folder is located at C:\Users\[username] \AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup.

For startup items for all users, the folder is located at C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Startup.

http://answers.microsoft.com/en-us/windows/forum/windows_7-performance/where-has-startup-gone/fa93e499-bd6a-4bd0-a8b7-1ba1958c4ccf