Does your taskbar keep disappearing when you open other windows to fullscreen? Well this should solve your problem:

1. Right click the start button.
2. Select 'properties' from the drop down menu.
3. Press the 'Taskbar' tab at the top of the 'Taskbar and Start Menu Properties' window.
4. Check the boxes that says 'lock the taskbar' and 'keep task bar on top of other windows'.

5. Press 'Apply' and then click 'OK'.