> I recently upgraded my machine which was running rh8 to rh9. The
> upgradation went smooth, but i could not login. Everytime i type my
> username and password it comes back again to the login screen (either
> in gui or in any tty).
Not sure the cause, but you can always reset your password.
I assume you're using grub as the bootloader, since it was rh8. At the
grub screen, select the kernel you want to boot and hit 'e'. Then use the
arrow keys to change to the line that starts with 'kernel'. Go to the end
of this line in the mini-editor, put a space at the end, and type the
number 1. Then hit 'b' to boot with this line. This will bring you up in
single user mode, which will leave you at a root prompt without prompting
for a password. From here, type:
to change root's password. If you want to change a user's password, type
# passwd username
When you're done, type