I have been on the phone helping someone with a RHEL 5 machine, but I was unable to solve the problem and was wondering if anyone else has ever run into this. When he logs in normally is kicked him back out giving an error of being logged in for less than 10 seconds. The recommended solutions were to check if there was available disk space and/or run fsck. Fail-safe login works perfectly fine, he is just unable to do his work through it. This machine is running on a laptop and has worked perfectly fine for over a month. What I have done so far to troubleshoot this issue:

*Checked the avialable space, he has over 50% avialable on every partition.
*Ran fsck during bootup.
*Created a new user and attempting to log in with the new user.
*Checked to see if partitions were mounted RW and not RO.

Reinstalling is not an option. I am looking for possible reason and solutions to call him back and present him with later today.

Is the user logging in from the command line or GUI? If the latter, try having him switch to a text prompt (CTRL+ALT+F1) and log in through that route. If that works, it seems that the graphical environment has some form of problem.

How is the user checking disk space and creating new users if he is unable to login?

He is using fail safe mode. I personally have not heard of fail safe mode to login, but it sounds like just a terminal login method(the same as CTRL + ALT + F1 I would imagine). The fail safe mode gave him full access to the machine through a text prompt. I would assume his main method is logging in through the GUI and did not think that the problem could be with that. Is there a way to check to see if the GUI is working properly? Is there a recommended way to reinstalling it if something is corrupt in the GUI?

I've never heard of fail safe mode (except in MSWin). but if you can get text mode (eg ctrl-alt-f2 or 3 or 4...) then login and run
and see if it works.
If it doesn't, you'll get bunch of msgs on the scree to help find the problem
You can also edit /etc/inittab and set
which brings the system up in cli mode by default, then try 'startx'.

"fail safe" ?? on rhel ???

i guess it could be the text boot
hopefully it is run 3 and NOT 1

have him boot "almost" normal
but during the 3 second count down hit < e >
then use the down key once and add a "blank space " then a 3
hit < enter> then < b>

( add a 3 to the end of the boot line )

boot into runlevel 3 AS ROOT

nano IS installed by default but i like MC( midnight commander) for the terminal boot

cd to the logs ( /var/log/????? and read them and find the error

the "boot.0.log " should have it
(check the name with "ls"