Should you decide to prevent specific items from starting up you can uncheck them in the System Configuration Utility. Though this method is fine it is ultimately best to remove them from the source. To access the common registry locations of these items take a look in the following areas:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce

If you have disabled items in the System Configuration Utility and would like to remove them from the registry also they can be found in one of the following locations:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SharedTools\MSConfig\startupfolder

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools\MSConfig\startupreg