You will need to boot up with a Workbench floppy disk before you can try to prepare and format your CF card. Being unregonised/unformatted, it might cause the A1200 to wait for 20 seconds first, before resuming booting from the floppy drive. Hopefully this is what happens, and it should continue to Workbench. You then need to use HDToolBox to prepare the CF card to be formatted and used as an Amiga hard drive. Once that's done, then you can finally format the drive. You really would be best to read through the whole thread on EAB, as those guys have been into this stuff for years.