Installing gnome again

[qweasdzxc]

I recently installed gnome from packages and it just isn't working right (bunches of errors whenever I try to run startx that I can't remember off the top of my head). But the question I have now is not how to fix this, but if I wanted to reinstall gnome from ports, what process would I need to go through to ensure I am not double installing something or going to cause who knows what problems if I just blindly 'make install' without taking care of my previous install?