How to fix blank screen with mouse pointer on Ubuntu install reboot?

I am trying to re-purpose my Dell Inspiron 8600 with Ubuntu 14.04 to be used as a low scale HTPC.

Here is what I have done so far.

I have created a live USB for installation. I had to force pae to get the installation to work.

The entire installation process goes well and prompts me to reboot to finish installation. It reboots, I get to the login screen with the drums, it looks like the desktop is going to fire up and then the screen goes black and the only thing active is the mouse pointer.

I can access the terminal through Ctrl+Alt+F1. I have tried several workarounds but I honestly don't really know what I am trying and if it is making any progress. Help would be greatly appreciated.

Note: as commented by @asocia, you will need Internet connnection for this solution to work.

Sometimes your desktop may not load due to problem with lightdm.

Press Ctrl+Alt+F4 then login using your username and password. Enter the following commands:

sudo apt-get purge lightdm
sudo apt-get update
sudo apt-get install lightdm
dpkg-reconfigure lightdm

Now type sudo shutdown -r now to restart.

It worked for me, try these steps:-

1. From Grub menu select "*Advanced options for Ubuntu".

2. Select the 1st "recovery mode" option ,that you see on your screen.

3. After that you will be navigated to Recovery Menu options.

4. In that select the 3rd option i.e. "dpkg Repair broken packages". And then enter the "Ok" button.

5. Enter to "Yes" button.

6. Then you will be navigated to the booting screen with 2 options 1st is "Continue [yN] and 2nd is Details [d].

7. Type y and hit enter.

8. Again hit Enter.

9. You will now navigated to Recovery Menu again and then select 1st option "resume Resume normal boot". and hit "Ok" button.

10. Again hit "Ok" button.

Now you will see your login screen with desktop background and everything works fine as it was before.

On Ubuntu 20.04 While you are in the black screen. You should do the following steps:

Press Ctrl+Alt+F4, then login using your username and password. Enter the following commands:

sudo apt purge gdm3
sudo apt update
sudo apt upgrade
sudo apt install gdm3

If it displays a warning, then choose gdm3 with arrow keys and press Enter.

If it didn't, then enter these two commands:

sudo dpkg-reconfigure gdm3
sudo service gdm3 start

Then restart from your Ubuntu login screen.

1) Press ctrl+alt+F4 2) Login with your user name and password 3) use command: sudo dpkg --configure -a 4) Now use command "sudo shutdown -r now" to restart

Try pressing CTRL+ALT+F4 and then type startx.
This is what solved it for me.