Reset iCal

I want to completely reset the ical client on my ppc imac (leopard). at one point i installed leopard server on a mini, wanting to sync their various ical clients. i found leopard server to be very buggy and sold it on craigslist and am now running tiger server only for file sharing (no other services). but i still have my one test client mac (ppc imac with leopard) that shows ical server in the left hand sidebar and ical server in the left hand sidebar in the accounts window of ical preferences. every time i start ical i get the following dialog: Error whilte refresshing, callendar http:// private.server:8008/principals/ uidsa004502e-eea7-4b79-900f-d1bca14ad1ef/ could not be found. the server settings in preferences lists aforementioned url as well. i cannot delete ical server from the ical preferences accounts. it keeps reappearing. i've tried trashing all kinds of plists to no avail.

I want to completely reset ical on this client mac (read: at least get rid of that server thing. there is no calendar data on this imac anyway). what do i need to trash to do this. i really do not feel confident using the terminal window. help please!