I was networking my laptop with a friend's PC notebook. I activated personal file sharing and windows sharing. All was going well till my finder quit. Then it started to cyclically start, stop, restart, stop, restart, etc. I tried eliminating processes that looked network related, stopped all sharing, restarted and zapped the pram. Now, whenever I start up, my harddrive icon and other finder icons won't even show up, and the finder is stuck in a start/stop cycle. What did I do to my machine, and how do I fix it?