You can start or stop programs from executing at boot up by adding or deleting them to/from the run Keys in the Registry. Windows loads programs to start in the following order; Program listed in the Local Machine hive, then the Current User hive, then theWin.ini Run= and Load = lines. then finally programs in your Start Up folder.

To add or remove programs in the Registry
1.Open RegEdit
2.Go to the desired Key
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows \CurrentVersion \Run
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows \CurrentVersion \RunServices
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows \CurrentVersion \Run
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows \CurrentVersion \RunServices
3. Add a new String Value and name it anything you like
4. For the value data, enter the path and executable for the program you want to run.

By adding the value to the HKEY_CURRENT_USER hive instead allows the program to start only when that user is logged on.

If you add the value to the RunOnce key the program will run once and be removed from the key by Windows.