Stuff reset after adding libraries

[RL]

I found this odd, but maybe it's normal.  I installed a bunch of
system libraries I didn't have before in /stand/sysinstall using the
CD. After that my login name (root was still there) was gone from
/etc/password (home directory was still there though), in which I
couldn't log in as non-root.  Also, my /etc/hosts was reset to the
default; my entries in that was gone.  Is this normal after installing
a bunch of libraries in sysinstall from the CD?