Actually I have added the Kali sources list in the ubuntu sources list two days ago. I added that for installing an application. Now after two days my ubuntu machine was giving crash reports, when i restart it, i was shocked that in start at grub it was showing Kali Linux after hitting enter it shows the ubuntu logo then the error System Running in Low Graphics. i tried the all methods i found here to solve system running in low graphics error but couldn't get success.
Thanks in Advance if someone solve my issue :).