OK - pretty sure I SHOULD have a valid OS9.2.1 CD now (thanks X) abd having worked out how to eject the CD I thought all would be plain sailing. However despite several attempts at holding the C key during boot it refuses to go there... is there an equivalent of BIOS boot sequence for the Mac? I only have a guest account until reinstall - so cannot even go to controls startup disc - is there any other way or anything i have missed? Google shows up some issues where a CD has to be exactly the right version for the hardware... could that be the issue? Thought it would get further before rejecting that. The existing OS shows as Mac OS Z1 -9.2.2 with ROM 9.0.1 if that helps.