As for the /home you might want to try to maybe capitalize your name in one distro and lower case in the other, so you have to different /home/$USER directories. Because it has to store things like app data and Desktop Enviroment/Window Manager data pertaining to each distro, and if you used say KDE in both, it would be confused. So lets say your username is novice26:
that's should fix that one, as far as I know.
As for the other boot question, if you post that good old lilo.conf I could see if there is something that I could help with. It just sounds like you are pointing to the wrong kernel image is all.