Don't laugh. I've been using CS6 on my Macbook Pro for many years. It's all I need. I recently migrated everything from the laptop to an older iMac. Now Photoshop is asking for the serial number and won't run. This was a legitimate purchase of CS6 Design extended but the serial number is unavailable. Any ideas on how to get the software running? It was fine on the laptop. Thanks for any advice.