Kawasaki vulcan 800 classic will not start now

DO NOT jump with a automobile!! TOO MUCH AMPERAGE!! Get a new battery, have the solenoid checked, have the starter checked (ALL by a professional!!) its one of these three..

right at the clutch lever on the bars there is three wires that clip into the clutch make sure it is in there good

For cold weather you need around the 200 mark. the 800 needs a 10AH battery. This will do the job: http://www.amazon.com/2004-2005-Kawasaki-Classic-Motorcycle-Performance/dp/B00688UE40

Rotella T6 synthetic 10/40
or Valvoline semi synthetic 10/40
Don't buy any oil additives like STP or Slick-50.

Most modern bikes will not start unless the battery is charged. Battery is probably dead, and you rectifier is most likely dead too. change those out with ones known to work and see if that changes it.

under the seat there is a reset button that taked a metal prong thingie (dont know whent it's called) you can use a paper clip - just jump the two terminals and try to start it,, doesnt happen all the time but it does happen.

battery dead? charging system not working? check regulator/rectifier and stator

Assuming you checked fuses and followed wiring for any signs of a short or connector undone. You're getting power to starter, but solenoid sounds dead if you have to bypass it.
If the engine spins but won't fire, I SUSPECT ingition problems. Encountered rain...is seal around ignition unit gone bad? That would splain the plug not firing.
Do you smell gas (oops...petrol) when you crank the motor? fuel getting to cylinder?
Check for water in fuel system.

no power to the coils, check fuses