Can't Turn Off ICloud And F'd Up Calendar

I have an iPhone with my Work calendar Synced with my work computer (outlook Calendar). Also, I have iMac 27" i5 with my Home calendar (iCal).This has worked fine and separetly for the last 3years.My home calenders allow me to organise my life with payments and is very important. My work calendar, well that speaks for it's self. I install iOS5 on iPhone and Lion on the iMac which unbekownence to me have iCloud syncing on and doing stuff that has totally corupted my iMac Home Calendar.My home calendar has my work calander mixed in with my home calendar and reminders popup every few minutes that I have already dissmissed.They won't stop popping up.The same one over and over and they go back a month or more.Additionally, when I try to add an event it sometimes puts it in very day instead of a monthly re-ocurring event and then it won't delete the event.I've tried to turn off iCloud, and it does all the right things and appears to turn off but then when I go back in it is on again.The Work Calendar (Windows 7 Office 2010) doesn't show any symptoms and has kept working as it should on my work computer as on the iPhone. Neither appear to be effected.I've tried all the delete files and reinsralls but iCal seems to just get more confused. It renames calendars and is totally out of control to the point of no return.I can't find any where which shows how to delete iCal and do a fresh install of iCal and not have iCloud sync.I have searched Google for months and months with no joy.What I need is to stop iCloud and it off permently as it appears to be a problem for how I use my apps.  I do not want to use iCloud for calander or anything just yet.I need to get my original .ics backup in iCal that I have and working on it's own and with out the cloud or syncing.

Info:
|| iMac 27" i5 and 20" G5 || Macbook intel & iBook G4 ||, Mac OS X (10.5), || iMac i5 and G5 || Macbook and iBook ||