TASKBAR not working correctly

plzzz help me ....im using windows 10 on lenovo g580 and my pc was working perfect in morning but now, i'm not able to click the start button or i can say the start menu is not working ......some of the icons like groove music and much more are not on the taskbar and their place is empty but i'm able to use the search which is in right side of the start button .....plzzz help me urgently as because tomorrow i've to submit my project ...plzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz