This is a royal pain. When it happened to me I had to uninstall the CC trials, and CS6. then run the CC cleaner tool (CS Cleaner Tool for installation problems | CCM, CS6, CS5.5, CS5, CS4, CS3). I also had to create a new Adobe ID that was not associated with the Creative Cloud and log into Adobe.com with that ID before running the CS6 installer again. This allowed me to enter my serial number to restore the perpetual license. If you need your serial number, you can log into Adobe.com using the ID that you used to register the product and it will be listed under you account under "my products."
Thanks Peter... Sounds dreadful...I'll give your advice a try but it looks as if I'm stuck somewhere in Italy 1000 miles from the installer disc for CS6...:-(..K
Ken Allinson / Sent from my iPhone
It might actually not be quite that dreadful. It would be worth a try just logging into Adobe.com with a new identity and trying to activate from the help menu before you wipe things. If you need an installer, you can download from Download CS6 products