Unfortunately these fixes work on some computers and not on others. I personally haven't found any change when unticking the Compiz Untiy Plugin under "Switcher" tab. It doesn't seem to make a difference. So the problem still remains on one of my older desktop computers that no method above would work. So I tried a different approach and it seems to work on every computer and is very consistent. Here is what I did.
First make a bash script. To do this create a "New Document" from your right click menu and choose "Empty Document". In this new document paste this:
Now save this file as "compiz-start". Make sure to set its permissions to "Allow executing file as program" ticked and move this file to /usr/bin/. You may also want to change to ownership to ROOT if you haven't already.
Now create a .desktop file to trigger this script. First right click and choose "New Document" then "Empty Document". Open this file and paste the follow text into it:
Name=compiz on start
Comment[en_US]=compiz on startup
Comment=compiz on startup
Save this file. It should save automatically as "compiz-trigger-start.desktop". Move this .desktop file to either your home autostart folder ~/.config/autostart (which will only work for the user) or place it into /etc/xdg/autostart which should make this fix work for all users of the system (or future new users).
This has worked for me on all computers that it was tested on...even the one that previously nothing had worked. You can tell that it works because just after the Desktop loads and the Unity bar shows up; the screen will reload itself...which is Compiz restarting. The "sleep 3" is critical to this working.
I hope that help you guys fix this "hot corners", "Show Desktop", "Spread Windows".