I can't access my inbox after a crash during a power outage.

<i>duplicate of [/questions/1587098] thread</i> My late husband's oid Mac Mini crashed during a power outage. Firefox is fine but TB says that the inbox is being used by another something and to wait to use it. I can't open it. I keep this computer active because his artworks and videos are on it. And I feel that he is still here if his computer is. You can also reach me at [edited email from community support forum]. I need to get in. Should I just restart? Or will it take more? I do get Robert's email on my iPhone and it is coming in.