Improper shutdown can cause totaly unusable system,so you can consider yourself lucky...
Well,if you want to go deeper into this,will you create new user and then post if that user have a .bashrc file in his directory.You can post all files in your home directory and from new user home directory also,that have bash in the name.I don't use Red Hat but it might have /etc/bashrc file or similar wich is default for all users on the system and actually all of the users .bashrc files are the same as bashrc file in /etc directory but there might be no bashrc files at all in /home directory,it all depends on the system.
I think that Bash prompt variable was damaged on shutdown so it changed to bash-3.00$ on restart and when you tried to fix it you damaged few more variables,but when you added good .bashrc file to your home directory things started to work.
Shell variable-The full pathname to the shell is kept in this environment variable. If it is not set when the shell starts, Bash assigns to it the full pathname of the current user's login shell and I guess you just didn't have your shell.
You might wanna read this