can you access the hard disk from your old computer? If no then where are you planning of getting the information from?

tgilltte said

I no longer can see anything on my last computer and need to access some emails sent. I downloaded Thunderbird on my new computer and get email online from my provider which I can download to the Thunderbird program. Is there any way that I can access mail sent on Thunderbird on the old computer?

I don't know how to access my hard drive. Can you explain what options I have to do this?

I suggest you consult a local computer technician to examine you old drive and determine if it can be placed in a USB case so you can access it.