My nephew was riding his 400 ex the other day .. 15 degrees out.. was in first gear and just quit.... come to find out the oil was a quart low....think the engine is fried????
Hit the started button and you can hear the started enguage, but stops....
I',m waiting for my brother to pull thee spark plug and try iy then...

 

It porb shouldn't be fried but I would def put some oil in it...did he just start it up and try and go without letting it warm up because if so it would be due to that and how cold it was out...try seeing if the gas is on and that you have enough voltage to crank the engine over.