Fixing Kali linux errors. (startx not found, "oh no! something has gone wrong" etc)

After your fresh install of kali, you might run into some problems.One of them consists of the login screen missing and returning:

"Oh no! Something has gone wrong.
A problem has occured and the system can't recover. Please contact a system administrator"

To fix this issue (a temporary fix), press CTRL+ALT+F1, it will take you to the terminal. From there, check if you can use the command "startx"

If you get the following error:

root@kali:~#startx

-bash: startx: command not found

The problem would be that you don't have the x window system functioning yet, install it by using the command:

  apt-get install x-window-system

Let it install and from there, you should be able to access your graphical user interface using "startx"


# apt-get update 
# apt-get install xorg 
# startx

Note: The steps above need internet connection, so you need to connect your pc to wifi or LAN. Here i am use wifi connection. or you can simply connect to your LAN wire to access the internet
To connect wifi, follow below instructions :

# ifconfig wlan0 does not turn on your wireless card. It gives you information about your wlan0. To turn on your wireless card, you would enter 
#ifconfig wlan0 up. Although, it's not always wlan0. To find out the name of your wireless card, type iwconfig, and look at the row that has some information in it, not 'no wireless extensions'.
To be able to run the commands ifconfig wlan0 up, 
# iwconfig wlan0 'essid name' 'key password' and dhclient wlan0, you need to be root. So, you have to put the word sudo before those commands (unless you're already logged in as root).
The password in the command iwconfig wlan0 essid name key password should be in hexadecimal. If you want to type the ASCII password, you would use iwconfig wlan0 essid name key s:password.
The command iwconfig wlan0 essid name key password only works with access points that use WEP as encryption. If the access point uses WPA/WPA2, you'll have to use another method to connect, found here: How do I connect to a WPA wifi network using the command line?

After you follows step by step above intructions, i am pretty sure that you has login linux in GUI. The last one is you open terminal and type this command 
# apt-get install gnome-core kali-defaults kali-root-login desktop-base
# reboot

Now your linux boot normally and the problem fixed.