command line – Very Big Problem that I am facing now. Please help me as soon as possible

I am a new user of ubuntu 20.04.2.0 LTS version. Yesterday, I have installed it in my pc. At the time of using ubuntu, the electricity has gone. And I am facing now the problem. Ubuntu Desktop is coming but all is blue, without firefox any software is not opening. And the terminal is not opening also. Now what should I do now please help me.