Crank but wont start?

The car was running fine this morning then when I came to go home it was as if the battery was dieing. All electric in the car was bogged down or not working and and when the key turned over completely it just ticked. And when I recieved a boost from someone all electric in the car was normal again but when I tried to start it was ticking still. I want to make sure this is definitely an alternator problem before I buy it in case its the starter or what not.

No prende. Pero hay chispa en los espares. En los inyectores hay coriente. Starte pero no prende la guagua.

Car just died one day and will not start now. Fuel pump turns on but no spark on any of the plugs. Mechanic said check crankshaft sensor. Checks out OK. Could the camshaft sensor or something else be wrong.