Only have Gnome Classic DE after installing Cinnamon

[JBigDog]

I was running 12.10 with the Gnome DE on the integrated graphics on my old Dell Dimension 4600 and of course i had no 3D. Yesterday my friend gave me a Radion 9600 and i popped that in and BAM, I had the regular Gnome desktop with fancy 3D with no configuration what so ever. I wanted to check out more desktop environments and today installed Cinnamon and that hosed me up. After reboot, you could not choose Cinnamon and Cinnamon 2D from the login manager (windows manager?) and even if you pick Gnome, it reverts to the Gnome classic. I uninstalled Cinnamon and of course the problem is still there. Any way to get my video settings back to the way it was when i just put the new video card in and everything was happy?

[JBigDog]

To give a little more background on this, ubuntu 12.10 was loaded from scratch and the Gnome DE was loaded afterwards. Everything worked fine in 2D mode. Friend gave me the Radeon 9600 and i put it in and on the first boot, i was able to get the 3D Gnome desktop and also the 3D untiy desktop. As soon as i loaded Cinnamon, i rebooted and my mouse was freezing every inch or so in the windows manager. the 2 icons for cinnamon and cinnamon 2d were just all white and if i picked either one, it would immediately go back to gnome classic. unity 3d still worked but then i uninstalled cinnamon and its dependencies and now all i can choose is gnome classic if i pick unity, it immediately reverts to gnome classic. mouse still is herky jerky at login prompt (windows manager if i have my terms correct) but as soon as i log into gnome classic, all seems to be fine. booted to gnome remix cd because i get 3d there and compared xorg.0.log to my machine and they are identical. not sure where to go from here. kinda new at Linux but im learning quick, especially when i screw stuff up and have to learn how to fix is quick :-)