Startbar Has dissapeared

One day i was playing my game (world of warcraft) and when i minimized the game the startbar was not there, not minimized or hidden, just wasnt there.  when this happened i opened up the control panel, and went to the task bar and start menu icon.  after i double clicked it, thats what my setting is, it highlighted then nothing happened.  so then i right-clicked it and again nothing happened.  So i just decided to leave it alone, and made sure it wasnt a virus by running a scan, and just recently when i have been minimizing my game with alt+tab has there been a second when the screens are changing the startbar appears in the middle of my screen then isnt there.  I have tried to see if the wallpaper was covering it up but it is not. thanks for the help