Task bar frozen

Hi

My computer's task bar is frozen. I shut it up properly but when I switched it on today, the task bar was frozen and I could not access my documents including excel. Even the time or clock forzen is not working. I cannot switch it off or restart it on using task bar. Yesterday i never opened internet so i dont know what could be the problem and how to fix it

Thank you

Hi

I just pressed pressed all keyboard buttons one by one and it started working.