I had Ubuntu 19.04 64 bit virtual machine I upgraded it to 19.10. After the upgrade finished the virtual machine has stuck on boot in VMware workstation 15. I had used a vmdk image for 19.04 available here www dot osboxes dot org slash ubuntu (less than 10 reputation can not post more than 8 links so have to keep it that way)
I made a couple of videos while I was upgrading the virtual machine ( I followed the instructions here www dot liquidweb dot com/kb/troubleshooting-please-install-available-updates-release-upgrading/) The videos are as follows
Ubuntu 19.04 to 19.10 upgrade messages
(less than 10 reputation can not post images links so read this without spaces in youtube links)
Now what could be the problem here as why a fresh upgrade is not able to boot into a system. What should I check in here or do to fix this? This is a fresh upgrade and what ever kept happening I let it happen. I logged in to tty6 I get following screenshot.  I have not restarted the system since the upgrade from 19.04 to 19.10 kept happening.
Then while I posted this question here I some how was able to restart the system and now I get
end kernel panic not syncing :VFS: Unable to mount root fs on unknown block (0,0)
Here is a video for the same.
Now I don't know what should I do. Why this problem came. How to debug this and fix this. Rather than creating a new VM by downloading a new ISO I am more interested to learn and fix the problem which has caused this.
part 5 https://youtu.be/JhFJEj2dUOM
I seem to have figured out something which might be applicable as mentioned https://askubuntu.com/a/41939/ the thing is before upgrading I did not note down on a paper or pencil as which kernel version was running or to what version the upgrade took place. I have been running defaults only so it should not be a problem. Someone in comments mentioned
"On my ubuntu 19.10 I've had to run apt install initramfs-tools in order to get update-initramfs command –" How can I execute these commands given my situation in video 5.
The thing is I do not know how to work with advanced boot menu please see the screenshots and videos I uploaded to understand my situation.
Even after booting into one of the kernels in advanced options I get kernel panic messages.
There is some knowledge gap in my situation I probably have figured out something which I should try but I am not able to understand how to proceed from here.