Notification Area Icons Behave Erratically

My PC is an HP e9150t quad core desktop using an Intel i7 CPU (920@2.67 GHz). I have 8 GB of RAM and am running Windows 7 Home Premium-64-Bit. It was purchased new from HP, in July 2009. The Microsoft products I am running include the 2007 versions of Outlook, Word, and Excel.

I've been having continual (and changing) problems with the Notification Area Icons. Every time I start my computer, I feel like I'm playing roulette. Regardless of choosing "hide icon and notifications," "only show notifications," or "show icon and notifications;" the resulting display doesn't seem to have any bearing on my choices.

As you can see from the screenshot I currently have 5 icons displayed on my taskbar. There are 6 programs which I chose "show icon and notifications." Sometimes I can choose 8programs to show icons and notifications, and 3 icons will display.

There are 21 programs marked to "only show notifications" and when I click on the arrow to the left of the taskbar icons, it shows 12 icons on the palate. Different days, the number changes.

Also, there are some programs that I don't even want there but cannot figure out how to delete them from being in this section.

Can you please help?
notification-area-icons.png