Check and make sure that the user's home directory actually did get created. I seem to recall that unless you specify the -m flag to useradd, the home directory is not created.
This is used with the useradd
command, not the adduser
command. What you might want to do is boot up to the first Slackware CD, and login as root and type setup
then you can configure your slackware system without re-installing. This is similar to typing sysinstall
in FreeBSD. Also, make sure that your use has permission to start X. If you get an error message, It helps if you can post the message.