Can you log in as root?
You'd type su to do this.
If so, you may have to faff with some permissions (have a look at man chmod).
Make sure you have permissions to /bin/bash, and your home directory.
If you can't log in as root, you'll need to reset the root password,like this :
Press shift key at the boot prompt and enter as, boot: Linux init=/bin/sh
This causes the system to boot the default linux kernel (with lable as 'linux') and run /bin/sh instead of its standard init. Now you have gained root privileges and a root shell. / is currently mounted read-only and many disk partitions have not been mounted yet.
# mount -n -t remount,rw /
# mount -avt nonfs,noproc,nosmbfs
# cd /etc
# vi passwd
# vi shadow
If the second data field in /etc/passwd is "x" for every username, your system uses shadow passwords, and you must edit /etc/shadow. To disable the root password, edit the second data field in the password file so that it becomes empty. Now the system can be rebooted and you can log on as root without a password.
People & Planet.
Don't Stand on your head - you'll get footprints in your hair.