Hi.
There are quite a few items that could have failed on you.
First, check the battery, to ensure that you do in fact have electricity.
If it has sat for a long time, then it could have a cell that went out in the battery.
A bad cell in the battery will **** the power out of all the good cells.
Next, if there is power in the battery, the next thing to check is the circuit breaker assembly. There actually three components in the assembly, and any one of them can fail.
Next, you might want to check the electronic ignition, as it can fail also.
Next, check the handlebar switches
Next, check out the ignition switches
The only other think other than broken wire somewhere is the voltage regulator
These are all the electrical components on your Harley.
I hope this helps you out.
Good luck to you, and have a good day.