I am using Mint Cinammon 17.1 Rebecca. Last night I installed synaptic package manager ( maybe it was already there :!: :!: ) and typed ubuntu ( was trying to changeto other desktop environments ) and ticked true all the options that came in ( mostly which i thought would be related to graphics, visuals and themes etc ). Now after logging out and loggin in, in the desktop selection menu i cant see all the downloaded desktops, or maybe its just the list is too big to be shown in there, its the gnome login most probabaly coz thats what is written on the bottom of the screen, i can select lubuntu, gnome and cinnamon from that list, though i remember installing kubuntu and xubuntu desktops too. so what happens now is if i select gnome or default or lubuntu, i get a error mesage dialougue box, it says report error or not, but no option to check what error is there, in lubuntu i cant see my mouse pointer anywhere, in gnome i can my pointer but i can do nothing like shouldn't something pop up at the corners, or even the minimize, maximize, close icons are gone, keyboard shortcuts are useless, but display and the first guide window is there, and coming to cinnamon default, some apps i can see the mouse pointer like firefox and terminal and some i cant like chromium and vlc.

My experiences over the years have shown me that making sweeping installations such as this, choosing all options, can take forever, can backfire as it apparently has done here, and can lock up the system in the midst of the install, leading to system instability.

A better method if you wish to try and see lots of features, explore all variations is to consider incrementally, i.e. piece by piece, installing features so that you do not encounter big potential problems such as what you're describing.

Considering the very "no holds barred" method you followed, the best I can recommend is a clean install. And if you wish to explore graphical theme or graphical decoration possibilities:

1. Consider doing this on an install where if things get screwed up, it doesn't derail any work or personal data that's important
2. Make a special install, use like a multiple boot option from the bootloader where you know that installation A is your primary working Linux and installation(s) B, C, ... are versions for experimentation

Another thing which can also be done with the incremental install of trying stuff is when you install one thing, you evaluate that one thing, decide if it's nice or garbage. If it's garbage you can uninstall it and further, you now know that installing that particular package is a waste of your time.

You also didn't ask a specific question here, you merely described the state of your system and an approximation of how it came to be that way.