First, I'd start with a known GOOD battery....
jumping doesn't always do the job, especially if your
original battery has an internal short.
Next, inspect the positive and negative battery cables
closely for any loose connections / corrosion.
Replace/repair where necessary.
After that, inspect the wiring FROM the starter TO the KEY switch.
There should be a fusible link in this line, and could be blown.
Power goes FROM battery... TO starter post... TO key switch .....
and then to lights/fuses for everything else.
Just Common Sense......
err....I'm not a Doctor, but I'll take a LOOK ! !