iCal won't delete calendars and restores those that have been forcibly deleted

I'm trying to delete all my past events from iCal so as to start with a completely empty calendar again. This is necessary for what I want to do. I deleted them using the menus (according to the instructions in the iCal handbook). And then, after 30 seconds, they reappear.

So then:

1. I quit iCal
2. I moved the following files to a folder called Junk:
   1. User/Library/Caches/com.apple.iChat
   2. User/Library/Calendar (the whole folder)
   3. User/Library/Preferences/com.apple.iCal.helper.plist
   1. User/Library/Preferences/com.apple.iCal.helper.plist.lockfile
   2. User/Library/Preferences/com.apple.iCal.plist
   3. User/Library/Preferences/com.apple.iCal.plist.lockfile
3. I then renamed the removed folder and individual files and put a file type of .avi at the end
4. I then trashed them
5. I then secure-emptied the Trash
6. I then rebooted
7. I logged in and opened iCal and ... iCal "reconfigured" until all the events were there again. I have no idea where it retrieved them from.

I wonder what I have to do to get rid of these calendars so I can start again. Can anyone help?

I have an iMac running Lion Server, though the Server is not active or configured and I'm just relying on the basic installation.