boot problems which don't make sense to me

[eipapp]

My machine is a HP - Pavilion 23. I was running Ubuntu 14.04 LTS and decided I wanted to run Ubuntu Mate DE along with it. I installed Mate 14.10 via PPA and on boot got the Mate desktop but the it immediately then showed the standard Unity desktop environment. It was like booting into Unity but with the Mate splash screen. I then decided to just install Mate (without Ubuntu) and it installed fine, however, it then would NOT boot. I scrapped that plan and went to Mint Cinnamon 17.1 and again it installed but would NOT boot. In both cases it would appear that it was trying to start up but after a while would go to a blank screen.
Out of ideas I went back to Ubuntu 14.04 and presto, it installed and booted just fine, thank you. I even installed Ubuntu Gnome along with it so that I can log out of one DE and switch to the other and I'm having no issues at all.
What I can't seem to get my head around, given that both Mate and Mint are Ubuntu based, is why I can't install and run either of them the same as I do Ubuntu. Would really love to know why this is.
Any help in solving this, to me, rather odd situation would be greatly appreciated. For what it's worth (and it may not be worth anything) I was running Fedora 21 Gnome 3.14 before running into all these issues.

Thanks
Bruce

[grahammechanical]

I am not sure if you are talking about installing different distributions in a dual boot kind of set up or are installing alternative desktop environments and user interfaces on to an existing Ubuntu install. Or doing both.

I am also not clear by what you mean by "would not boot." Does the OS boot but not load to a working desktop? Or does the OS not boot in the sense that the loading process stops with some error message or a black screen?

Regards.

[eipapp]

Initially it was my intent to set up a alternative desktop environment so that, for example, I could log out of Ubuntu then log into Mate.

As to the not boot issue, after installing the OS it would not load to a working desktop. There were no error messages just a blank/black screen.

Regards,