Try this key: [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
A better solution would be to click on [Start] the type in "MSCONFIG" to start up System Configuration. Then click on the [Startup] tab and that will show you all the startup items in Windows - this includes both the Local Machine startup and the various user profile start up items too.
Then you can disable them by remove the tick next to them.
Hope that helps.