Applications or services set to start when the system starts
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

Software to run once at start up, the subkey may be set here
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce

If the key is set to 2, the service starts automatically;
if it is set to 3, the service must be started manually;
if the key is set to 4, the service is disabled.

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services

The values are run when the specific user logs in.
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run