How to repair my system after installing xmonad?

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http://askubuntu.com – I was using Lubuntu although other DE were installed. I was curious (like the cat) to see what xmonad is, installed it in synaptic and now my system is unable to load. The dual boot list appears, when I select linux it starts loading (the bubles under lubuntu logo), then is stuck with a black screen and messages: speech-dispacher disabled: edit /etc/default/speech-dispatcher *Stopping GNOME Display Manager *Stopping save kernel messages *Stopping log initial device creation *Starting enable remaining boot-time encrypted block devices *Starting configure virtual network devices *Starting (HowTos)