I know there's not much detail I'll be able to provide, but if the info below could give you a hint of what is going on, please help.  A colleague was sharing screen with me yesterday, using RHEL's default remote desktop software, and I was viewing the screen with TigerVNC which is also installed by default in CentOS. We were working on Netbeans.  The default .bashrc file was already in my colleague's PC, and I opened it and added a few aliases like alias f='cd ..;ls;pwd' and alias bashrc='gedit ~/.bashrc;source ~/.bashrc'. Then did a source ~/.bashrc. My colleague had also added some add-on's in Firefox a few days before the screenshare.  Everything was working fine, and we ended the screenshare session and both of us shutdown our systems. Nothing more was done.Today morning when my colleague logged into the RHEL system, the .bashrc file was missing and on opening Firefox, the addon's that were installed were also missing. It was like as though Firefox was opened for the first time.  It's quite obvious that the profile settings disappeared, but what could cause this? Nobody accessed our systems after we had shutdown.  Any idea what could cause the user profile settings to just vanish?  ps: The settings of the root account were not affected. 
Logged into RHEL 6 and profile settings are missing
rhel;bashrc;settings
On finding the solution I thought of deleting this question, but considered leaving it here in case someone else goes through the same situation.  What happened that day, was that I had opened Nautilus (File explorer) menu and navigated to Edit -> Preferences -> Views -> Show hidden and backup files. After the Remote desktop sharing session was over, my colleague (who was new to Linux) opened up Nautilus and saw a lot of extra files (the hidden files which were now visible).  Not knowing where those files came from (and not wanting to delete them, just in case they were important), my colleague moved all of those hidden files into a separate folder, shutdown the system and went home for the weekend.  Returning back on Monday morning, my colleague had forgotten about the files that were moved, and was puzzled as to why all the profile settings suddenly vanished, and thought it happened because I had put in a few aliases in ~/.bashrc.  I later located those files and we had a good laugh about it.