Why does my Windows task bar pop up and down

Every few minutes, even if there is no activity on the PC, my Windows 7 task bar pops up and down again.

Does anyone know what can cause this to happen?

Answer

Several things I can think of:

1. 
   

   There are 2 types of apps can bring up the taskbar - applications that show notifications (in Windows 7, just hide those notifications to avoid this behavior), or applications that simulate key strokes. It could be an application running in the background, or even a script using the SendKeys method.
   Try to see what's running on your machine (ProcessExplorer) and eliminate the applications one at a time until you catch the culprit.

   
   


2. 
   

   Another thing I can think of, that I've experienced before, is touch screen activity. Whenever I touched my screen, it popped up the bar. Ignore if you don't use a touch screen

   
   


3. 
   

   Finally, it can be that you have key stuck in your keyboard. It may even be a useless key that does nothing when manually pressed (like SysRq - why do they keep including it?).
   Try connecting a different keyboard to your computer and see if the behavior reoccurs.