Adding an SSD

After a failed original HD on my iMac 27inch 2010 model, I decided to install a 2.5inch Samsung 1TB SSD (without removing the existing HD). After recovering all saved data from my time capsule, the iMac failed to complete the restart procedure - hanging up on the white screen with apple and completion bar at 97%. SMC and PRAM reset. Any tips to further troubleshoot before I try to recover the data again (2 day process).

Regards,

Frank