Yesterday I updated from 10.04 to 11.10 and ended up with the Unity desktop. I was slowly getting the hang of it but wanted to make the launcher icons smaller. I installed Compiz per the help page, ran it, but couldn't figure out how to change the icon size. I closed the application and everything on the desktop vanished. I tried pressing the meta key twice (Windows key according to the help page) but nothing happened. Same for the alt keys (both of them) and the menu key. The only key combination that did anything (that I could find) was ctrl-alt-del which allowed me to log off and then I was able to shutdown.
What do I do to a) recover a working interface or b) startup in something other than Unity?