The unity has disapear from the login screen

[nathan soulfly]

Hi im using ubuntu 11.10.Yesterday i was trying to make my system have the effects and the cube on unity with CCSM, i tryed for hours by my self and with some videos i found on youtube and then i found a page from a thread here on this site and tryed the instractions it had.Finally i made only the effects work, it was very helpfull.Today i opened my computer and to the log screen i put my password with out checking the small gear on the right to see what was selected cause i new from yesterday i was last checked to UNITY (or UBUNTU as it appears on that menu) and it loged in GNOME.So i logout and try to select from the gear the unity (or ubuntu )but it wasn't there.The options i have left are GNOME , GNOME classic , GNOME classic with no effects and UBUNTU 2D which is the UNITY 2D environment.Help please.

THANKS IN ADVANCE