|Your system tray shows programs that are currently running so I'm assuming you mean your quick launch bar. |
Right click on the task bar and click on Toolbars, make sure there is a checkmark next to the Quick Launch option.
If the Quick Launch bar is already showing and you want to add icons to it, Go to Start, All Programs, find the program you want to put in your Quick Launch bar, right click on it and select Copy.
Now go back out to the Quick Launch bar and right click on it, click on Open. Now right click in the window that opened up and select Paste. This will put the icon in the Quick Launch folder. Do this for each program you want to show up in the Quick Launch bar.