Can't access Thunderbird I just downloaded to new desktop

I have a previous Thunderbird account, which resides on another computer. On my current Desktop, I downloaded Thunderbird, went to open and it says "Your Thunderbird profile cannot be loaded. It may be missing or inaccessible." I went this route because my original Thunderbird has many customized Files to which I put emails into. I can't figure out how to recreate that profile as your instructions are quite impossible to follow. Remember, most of your users are like me, a bit under the standard as far as programming skills. So, how do I get either: my original profile to be imported to my new computer, or, better, just open my new Thunderbird so I can use a different, newer set of email addresses? This is my preference. Please advise.