As the title suggests I can run X as root but not as a regular user. It's a fairly fresh install and I'm not positive I have the permissions down right. Frustratingly X seems to refuse to dump errors into my xorg.0.log so I have no idea what to do to fix it.

Here's what happens: I log into my regular user account then type startx. It loads up the nvidia splash then goes to the kde startup gui thing and then sits there flashing on Initializing components until I ctrl+alt+backspace back to console. I then shift+pgup but all I can see is frustratingly vague messages like: kdeinit: fatal IO error client killed. Nothing to point me in the right direction and when I go check the xorg.0.log the only logs there are from when I run X as root.

As for the permissions, here is the list of groups I have my reg user account in:
audio
cdrom
disk
floppy
man
plugdev
slocate
users
video

Perhaps there is some obscure X11 folder I need to change the permissions on? I haven't changed any folder permissions and the only things I've installed since the computer got up and running was the nvidia driver and a firefox plugin called adblock.

Anyone have any ideas?

Is there something in ~/.xsession-errors perhaps?
Alternatively, you could try switching to runlevel 4 and log in as user. Does that work?

~/.xsession-errors doesn't exist in either my root folder or my reg user folder.

telinit 4 doesn't help either. Still stalls at the same spot.

Try removing or moving your ~/.kde directory and then try again. Give it a lot of extra time the first time to setup all of the default settings properly. Does xfce or fluxbox work for a regular user?

idk, for some reason I had a similar problem but it worked when I did "startx -m" idk, may not work for you but it did for me.

Check ownership and permissions on the home directory,subdirectories,and files of
the user that can't startx. You are looking for stuff that is owned by root.
There should not be any, if any are found you need to chown them back to said
user.

A quick way to do this is
chown -R dugan /home/dugan
where dugan is that user's name on the system.

I believe from your description that this appears to be a KDE problem not an X problem.

Rename the .kde folder in the user directory to .kde-old and copy the .kde folder from root (making sure you change the permissions to your own user) and see if that helps.

Actually, there's no need to copy root's .kde folder. KDE is supposed to create one at the first run.
Would be interesting to see what error messages KDE produces when "flashing"... Try to go to the first console and see if there's anything interesting there. Ctrl+Alt+F1

I suggested it merely because otherwise you'd have to reconfigure everything from scratch.

Also I suggest that anybody be very careful when you mess with .kde folders, because they also hold some important data like mail downloaded using kmail and KDE contacts.

Maybe, the OP can try a different WM just to rule out a KDE-specific problem.
Something like
echo fluxbox >> .xinitrc
startx

OK I checked the home folder's ownership and the reg user owns it. I renamed the .kde folder and got the same issue. Luckily it actually cranked out a .xsessions-errors this go around so here we go:

xset: bad font path element (#595), possible causes are:
Directory does not exist or has wrong permissions
Directory missing fonts.dir
Incorrect font server address or syntax
startkde: Starting up...
kbuildsycoca running...
ksplash: Fatal IO error: client killed
kdeinit: Fatal IO error: client killed
kdeinit: sending SIGHUP to children.
klauncher: Exiting on signal 1
kdeinit: sending SIGTERM to children.
kdeinit: Exit.
DCOP aborting (delayed) call from 'kded' to 'klauncher'
DCOP aborting while waiting for answer from 'kded'
kded: Fatal IO error: client killed
Warning: connect() failed: : No such file or directory
ksmserver: cannot connect to X server :0

I'm going to try fluxbox now to see if it's just a kde issue.

EDIT: fluxbox works. So I guess it is a kde problem.

EDIT #2: Being that it has been quite a while since I've used linux how do I switch the default X back to kde? I would like to fix the problem.

You can troubleshoot the "bad font path" problem by looking at the output of

xset -q

and checking which font paths displayed are incorrect. But I doubt that this is the cause of KDE acting up.

is it safe? remove all /home/user/.serverauth.xxxx -> clean /tmp/ksocket-username -> clean /tmp/xauth.XXXXXxxxxx -> clean '/var/tmp/kdecache-usename'

The stock Slackware does not create the file. If you want the file created then look here:

A More Intelligent startx Script

You can get the .xsession log to appear in run level 4 by editing /etc/kde/kdm/kdmrc:

Also, when you boot into run level 4, there will be a kdm.log in addition to the Xorg.0.log. However, the kdm.log typically is nowhere as informative.

If you want more verbosity in Xorg.0.log then use the -logverbose as a server argument with the startx command: for example, -logverbose 10.

KDE needs to establish some temporary directories. They are:

$HOME/.kde/cache-$HOSTNAME linked to /var/tmp/kdecache-$USER/
$HOME/.kde/socket-$HOSTNAME linked to /tmp/ksocket-$USER/
$HOME/.kde/tmp-$HOSTNAME linked to /tmp/kde-$USER/

Thus, be sure your user account has write/change permissions to /var/tmp and /tmp. Typically both directories are assigned 777 permissions.