Sounds like x isn't starting. Probably a problem with you xorg.conf file. Login and check through your /var/log/xorg.0.log file, look for messages that might explain why x is unable to start.
To login, it depends on how you installed. Often it is just linuxmce and linuxmce as your username and password. But check on the wiki web site as it has a big article explaining exactly how to logon under all combinations and circumstances!