Abdul Mannan's questions

I am facing a problem about "no space left on device" as shown in the Figure below.

I am relatively a newbie and don't know much about linux. I am using Ubuntu 18.04. Checking out various blogs about my problem such as this one (which suggests that I should increase my drive size) and this one (which is quite similar to my problem) also highlights the same problem but does not specify any solution.

Can you please help any solution? Thank you so much for your attention.

PS: I have also taken screen shot of df -h as shown below

I am using 64bit ubuntu 15.04 and in the hardwared; NVIDIA GeForce GT630 graphic card is attached. I have downloaded driver for this graphic card from the website given in the official website as shown in Fig.NVIDIA-GeForce GT630-website-screen shot, I have followed every method mentioned in different sites such as

1. press Ctrl+alt+F1
2. Type in, sudo service lightdm stop and then
3. to run as root ls -i
4. sh. graphic-driver.run
5. sudo service lightdm start

I have crashed my Linux 15.04 3 times in this way and now I am unable to even re-install it which is a separate story. Please, help.