Hi SPULUKA, thanks for your advice.
Juniper won't renew support for this device since it's too old (EOL).
Yes, I get to the loader prompt and I can upload versions using TFTP. That's how I uploaded and tried various versions of ScreenOS.
I would like to get the older version of the ScreenOS to try, but it looks like Juniper doesn't support it any more.
I was hoping someone would have an old saved version they could provide to me.