One day I accidentally removed all python libraries/modules from my linux. Then I restarted my PC and suddenly my Desktop gone away. So after searching online I have fixed my issue and I am sharing this resolution with you all. So what is happened with me that I have removed all python dependencies from my linux. So linux not able to find those dependencies and I am only able to see the screen with no desktop.
Now, you need to access shell to reinstall all dependencies. Now press "Ctrl + Alt + F1" after that you are inside shell. Once there, try reinstalling Python and anything else you may be missing.
sudo apt-get install python3-all sudo apt-get install gnome-terminal
If nothing seems to work properly then either it may be a case that your dependencies have been messed up. Try installing all of the desktop components again. This should give you all of the dependencies you need.
sudo apt-get remove ubuntu-desktop sudo apt-get install ubuntu-desktop