Double click your Macintosh HD icon, double click the Library folder, double click the StartupItems folder. The StartupItems folder will contain startup programs or sub folders which contain startup programs.

Look them over and decide if you need any of them to start when the system boots and\or run in the background. If you should decide that you do not need a certain program you can remove it from the StartupItems folder.

But before you remove anything from the StartupItems folder be very sure it's not needed or necessary. You could create a sub folder in the Library folder and name it "backup" or something similar and move the unwanted startup programs to that folder - just in case. Then if it turns out to be something that you need or must run at startup, you can always move it back.

Regards.